Fix no recents animations after unify

Recents animation doesn't work once AppWindowToken and ActivityRecord
unified because the mLaunchTaskBehind is updated to false too early
while running recents animation. We should also defer the updates until
recents animation completed.

Bug: 80414790
Test: atest RecentsAnimationTest
Change-Id: Ie1dd5c580b8f1c7cc66c7e12590a31398e59b2b5