Make `Manage Extension Account Preferences` more discoverable

[TylerLeonhardt]

Right now it's only in:

• The Command Palette
• in the context menu of the extension:
  
• The gear in the "Manage Trusted Extensions" quick pick
  

But even still folks have a hard time finding it. I will add it next to Manage Language Model Access.

[TylerLeonhardt]

Verification: You should see Manage Extension Account Preferences in the Account Menu now.

[alexr00]

Thanks for adding this!