Migrate WindowContext#onConfigurationChanged to ClientTransaction (2/n)

Introduce WindowContextConfigurationChangeItem and
WindowContextWindowRemovalItem to dispatch non-activity window
change/removal. This is not functional until the server side is hooked.

Bug: 290876897
Test: atest FrameworksCoreTests:WindowTokenClientControllerTest
Test: atest FrameworksCoreTests:WindowContextConfigurationChangeItemTest
Test: atest FrameworksCoreTests:WindowContextWindowRemovalItemTest
Test: atest FrameworksCoreTests:ActivityThreadTest
Change-Id: I4e6346cc267d7ccb8b3ab0e8c6eb67c8fa12e091