Add adb commands to enable camera compat for all apps.

These commands will be used to make camera compat testing easier.

Flag: com.android.window.flags.enable_camera_compat_for_desktop_windowing
Test: atest WmTests:AppCompatCameraOverridesTest
Bug: 29732968
Change-Id: I6287508be0be4280a824623c08dcf964e7ce9c50