Do not crash DesktopVisibilityController on unknown displays

Instead of requiring that a valid display ID is given to
the APIs in `DesktopVisibilityController` and crashing the Launcher,
this CL lets the code handle invalid IDs gracefully, and adds a test
that fails without the fix.

Bug: 392986431
Test: atest NexusLauncherTests:com.android.launcher3.statehandlers.DesktopVisibilityControllerTest
Flag: com.android.window.flags.enable_multiple_desktops_frontend
Flag: com.android.window.flags.enable_multiple_desktops_backend
Change-Id: Id1bc7876ce654b96191c85089557b9279963acd8
2 files changed