Improve app pairs disabled state

This CL fixes 2 issues with app pairs:
- When an app pair is incompatible with the screen size due to a non-resizeable app (e.g. Camera), the app pair will now be properly disabled and display an error message. If the user is on a foldable, it will prompt the user to unfold their phone.
- The app pair icon will now properly redraw with lower opacity when it is disabled.

Fixes: 323088270
Test: Manually paused and unpaused apps, created Camera app pairs and tested with foldable
Flag: ACONFIG com.android.wm.shell.enable_app_pairs TEAMFOOD
Change-Id: I66514c96bc19f480c9788661e4dffaa5b1cdc2ca