Modify Desktop Windowing incompatible task heuristic

Update heuristic to exclude activities which are not displayed so we
remain in the freeform state.

Flag: com.android.window.flags.enable_desktop_windowing_modals_policy
Test: atest WMShellUnitTests:AppCompatUtilsTest
Test: atest WMShellUnitTests:DesktopTasksControllerTest
Test: atest WMShellUnitTests:DesktopModeWindowDecorViewModelTests
Bug: 364012155
Change-Id: I414fc9977adf0a20f645d39f540299fdcc214588