Set the correct PiP mode at the end of the PiP animation.

Previously, we didn't update the PiP at the end of the PiP animation
when the animation type if FADE_IN. That results in map getting stuck
in the PiP even after user puts the PiP window back to fullscreen. This
change takes care of it by covering the FADE_IN case.

Fixes: 129545599
Fixes: 130550078
Fixes: 131812563
Test: atest PinnedStackTests
Change-Id: Ib40b9c6bafaa50f2f0b03cb88ae819bfe75547b5