Add base scenario test for enter desktop mode with app handle menu.

Video recording of the CUJ test: b/351956025#comment2

Bug: 351956025
Test: atest EnterDesktopWithAppHandleMenu
Flag: com.android.window.flags.enable_desktop_windowing_mode

Change-Id: Ida3a640f16c4c8433d25fbed796d3797a5b8e03a
Signed-off-by: Devarshi Bhatt <devarshimb@google.com>