how to include extension attributes in rest API call of products?

i have made a drop down named test_attribute and multi_attribute for products and i want to show that into api call of products as well i have made extension_attributes.xml but nothing in extension_attributes.xml shows up in api call can some body help?
extension_attributes.xml

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:Api/etc/extension_attributes.xsd">
    <extension_attributes for="MagentoCatalogApiDataProductInterface">
        <attribute code="multi_attribute" type="string[]" />
          <attribute code="test_attributee" type="int" />
           <attribute code="is_featured" type="string" />
    </extension_attributes>
</config>

db_schema.xml

<?xml version="1.0" ?>
<schema xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:Setup/Declaration/Schema/etc/schema.xsd">
    <table comment="Catalog Product Table" engine="innodb" name="catalog_product_entity" resource="default">
        <column comment="Featured Product" length="64" name="is_featured" nullable="true"  xsi:type="varchar"/>
    </table>
</schema>

di.xml

<?xml version="1.0" ?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:ObjectManager/etc/config.xsd">
    <!-- <preference for="FSDTestApiProductsInterface" type="FSDTestModelProductsManagment"/> -->
    <type name="MagentoCatalogApiProductRepositoryInterface">
        <plugin name="product_repository_plugin" type="FSDTestPluginProductRepositoryInterface" />
    </type>
</config>

productRepositoryInterface.php

<?php
namespace FSDTestPlugin;

use MagentoCatalogApiDataProductExtensionInterface;
use MagentoCatalogApiDataProductInterface;
use MagentoCatalogApiDataProductExtensionFactory;

class ProductRepositoryInterface
{
    /**
     * @var ProductExtensionFactory
     */
    private $extensionFactory;

    /**
     * @param ProductExtensionFactory $extensionFactory
     */
    public function __construct(ProductExtensionFactory $extensionFactory)
    {
        $this->extensionFactory = $extensionFactory;
    }
    public function afterGet(
    MagentoCatalogApiProductRepositoryInterface $subject,
    MagentoCatalogApiDataProductInterface $entity
) {
    $ourCustomData = $this->customDataRepository->get($entity->getId());

    $extensionAttributes = $entity->getExtensionAttributes(); /** get current extension attributes from entity **/
    $extensionAttributes->setOurCustomData($ourCustomData);
    $entity->setExtensionAttributes($extensionAttributes);

    return $entity;
}
public function afterSave(
    MagentoCatalogApiProductRepositoryInterface $subject,
    MagentoCatalogApiDataProductInterface $entity
) {
    $extensionAttributes = $entity->getExtensionAttributes(); /** get current extension attributes from entity **/
    $ourCustomData = $extensionAttributes->getOurCustomData();
    $this->customDataRepository->save($ourCustomData);

    return $entity;
}

    /**
     * Loads product entity extension attributes
     *
     * @param ProductInterface $entity
     * @param ProductExtensionInterface|null $extension
     * @return ProductExtensionInterface
     */
    public function afterGetExtensionAttributes(
        ProductInterface $entity,
        ProductExtensionInterface $extension = null
    ) {
        if ($extension === null) {
            $extension = $this->extensionFactory->create();
        }

        return $extension;
    }
}

UpgradeData.php

<?php
/**
 * Copyright © FoodServiceDirect, Inc. All rights reserved.
 * See COPYING.txt for license details.
 */
namespace FSDTestSetup;

use MagentoFrameworkSetupUpgradeDataInterface;
use MagentoFrameworkSetupModuleContextInterface;
use MagentoFrameworkSetupModuleDataSetupInterface;
use MagentoEavSetupEavSetupFactory;

class UpgradeData implements UpgradeDataInterface
{
    /**
     *
     * @var type
     */
    private $eavSetupFactory;

    /**
     *
     * @param EavSetupFactory $eavSetupFactory
     */
    public function __construct(EavSetupFactory $eavSetupFactory)
    {
        $this->eavSetupFactory = $eavSetupFactory;
    }
    /**
     * {@inheritdoc}
     */
    public function upgrade(ModuleDataSetupInterface $setup, ModuleContextInterface $context)
    {
        $setup->startSetup();

        if (version_compare($context->getVersion(), '1.1.1', '<')) {
            $eavSetup = $this->eavSetupFactory->create(['setup' => $setup]);
            $eavSetup->addAttribute(
                    MagentoCatalogModelProduct::ENTITY,
                       'test_attribute',
                        [
                           'group' => 'General',
                           'type' => 'int',
                           'label' => 'Include Test Attribute',
                           'user_defined' => false,
                           'backend' => '',
                           'input' => 'boolean',
                           'visible' => true,
                           'wysiwyg_enabled'   => false,
                           'source' => MagentoEavModelEntityAttributeSourceBoolean::class,
                           'required' => false,
                           'sort_order' => 150,
                           'default' => '0',
                           'global' => MagentoCatalogModelResourceModelEavAttribute::SCOPE_GLOBAL,
                           'used_in_product_listing' => true,
                           'visible_on_front' => false,
                        ]
               );

        }
        if (version_compare($context->getVersion(), '1.1.4', '<')) {
            dd("jfjf");
            $eavSetup = $this->eavSetupFactory->create(['setup' => $setup]);
            $eavSetup->addAttribute(
                    MagentoCatalogModelProduct::ENTITY,
                       'multi_attribute',
                        [
                           'group' => 'General',
                           'label' => 'Multiselect Attribute',
                           'type'  => 'text',
                           'input' => 'multiselect',
                           'source' => 'FSDTestExtensionModelConfigProductExtensionoption',
                           'required' => false,
                           'sort_order' => 30,
                           'global' => MagentoCatalogModelResourceModelEavAttribute::SCOPE_STORE,
                           'used_in_product_listing' => true,
                           'backend' => 'MagentoEavModelEntityAttributeBackendArrayBackend',
                           'visible_on_front' => false,
                           'visible' => true
                        ]
               );

        }
        if (version_compare($context->getVersion(), '1.3.1', '<')) {
         
            $eavSetup = $this->eavSetupFactory->create(['setup' => $setup]);
            $eavSetup->addAttribute(
                    MagentoCatalogModelProduct::ENTITY,
                    'test_attributee',
                    [
                       'group' => 'General',
                       'type' => 'int',
                       'label' => 'Include Test Attribute',
                       'user_defined' => false,
                       'backend' => '',
                       'input' => 'boolean',
                       'visible' => true,
                       'wysiwyg_enabled'   => false,
                       'source' => MagentoEavModelEntityAttributeSourceBoolean::class,
                       'required' => false,
                       'sort_order' => 150,
                       'default' => '0',
                       'global' => MagentoCatalogModelResourceModelEavAttribute::SCOPE_GLOBAL,
                       'used_in_product_listing' => true,
                       'visible_on_front' => false,
                    ]
               );

        }
        if (version_compare($context->getVersion(), '1.4.0', '<')) {
         $eavSetup = $this->eavSetupFactory->create(['setup' => $setup]);
         $eavSetup->addAttribute(
                 MagentoCatalogModelProduct::ENTITY,
                    'multi_attribute',
                     [
                        'group' => 'General',
                        'label' => 'Select Titles',
                        'type'  => 'text',
                        'input' => 'multiselect',
                        'source' => 'FSDTestModelAllTitles',
                        'required' => false,
                        'sort_order' => 30,
                        'global' => MagentoCatalogModelResourceModelEavAttribute::SCOPE_STORE,
                        'used_in_product_listing' => true,
                        'backend' => 'MagentoEavModelEntityAttributeBackendArrayBackend',
                        'visible_on_front' => false,
                        'visible' => true
                     ]
            );

     }


        $setup->endSetup();
}
}