Let InsetsStateController apply mPendingControlTarget

When mPendingControlTarget is ready to be the real control target,
InsetsSourceProvider should ask InsetsStateController to update it
instead of updating it silently. Otherwise, mControlTargetProvidersMap
and InsetsSourceProvider#mControlTarget might be not synchronized.

Fix: 340445972
Flag: NA
Test: atest InsetsStateControllerTest
Change-Id: I3dd255fd11a7affe575299a09d28435ea986fdc7