Connect DesktopTaskChangeListener with DesktopRepository. This migrates existing code from FreeformTaskListener.

Bug: 332682201
Test: atest DesktopTaskChangeListenerTest
Test: atest FreeformTaskListenerTests
Test: atest FreeformTaskTransitionObserverTest
Flag: EXEMPT (already flag-guarded)
Change-Id: I6b5fb097bfcd186423b30ec33271d40e9d764818
8 files changed