I’m running Microsoft® Outlook® for Microsoft 365 MSO (Version 2605 Build 16.0.20026.20166) 64-bit on my computer in Classic mode. Unfortunately last week it force-updated on me and changed a bunch of things, one of which was that now when I open an e-mail in a new window, or start a reply in a new window, I see a “Copilot” dropdown menu, which either shows “Chat” and “Summarize” or “Chat”, respectively:

Is there a way I can remove this menu from my Outlook client? I looked in the Options menu and didn’t see anything that looked related.
I’m open to a GUI setting, an Account-level setting, a Registry setting change, or possibly even manually deleting some specific file(s) from my computer to achieve this.
Bonus points if the solution eliminates all Microsoft Office Copilot content from my computer, including “Summarize” buttons, etc.