Don't create compatDisplayInsets if has fullscreen override

Don't allow SCM if system has overridden app to full screen to prevent
letterboxing or SCM when resuming activity.

Always show aspect ratio icon if user has set app to full screen.

Fix: 330887629
Test: atest SizeCompatTests
      atest UserAspectRatioSettingsWindowManagerTest
      manual
Change-Id: I1d7fdad2f48b6a68f52a8aeb4d6b864143a93b1b