Clear bounds of fullscreen leaf tasks

...not created by organizers

From the discussion of a previous uncommited CL we plan to restore the
bounds clearing when a leaf task is in fullscreen.

This restores a piece of logic that was removed in the commit
939b27cb and
3b911d9d.

Bug: 262317904
Test: ImeInsetsControllerTest#testChangeSizeWhileControlling on CF PC.
Test: atest TaskTests#testBoundsOnModeChangeFreeformToFullscreen
Test: atest ContentRecorderTests#testOnTaskBoundsConfigurationChanged_notifiesCallback
Test: atest TransitionTests#testVisibleChange_snapshot
Test: atest TransitionTests#testTransitionVisibleChange
Change-Id: I9b5a4d5dd0e2c519342f5ea8dc09ce2ef1e39bce