Disable Maximize Menu when in desktop's immersive

Disables hover to open or long click to open the maximize menu when in
desktop immersive mode.

Flag: com.android.window.flags.enable_fully_immersive_in_desktop
Bug: 372319957
Test: enter desktop immersive, click/hover over button, verify it does
not open the maximize menu

Change-Id: Ia7faebd505318ae5be10dc5df3cf12a611c848d7