[1/n] Hide desktop button in overview for incompatible tasks

Move `AppCompatUtils.kt` to shell/shared so can be used by launcher.
Refactor functions to not rely on taskInfo object as not available in
launcher.

Flag: EXEMPT refactor
Test: atest WMShellUnitTests:DesktopModeWindowDecorViewModelTests,
      atest WMShellUnitTests:DesktopTasksControllerTest,
      atest WMShellUnitTests:SystemModalsTransitionHandlerTest,
      atest WMShellUnitTests:DesktopModeCompatPolicyTest
Fixes: 389923274
Change-Id: I81344176003bc3d6e0a444e9bb1ade1ebdb88764