Ensure visibilities after TaskFragment WCT

Those WCT operations can change activity visibility. Without this
change, some activities visibility update may happen too late to be
included in transition animatoin.

Bug: 196173550
Test: Test with demo app that the activity visible is updated.
Test: atest WmTests:TaskFragmentOrganizerControllerTest
Change-Id: I78e6e1953f7ad2b733bc819002ac5d1d4929e727