Remove delayed snap scene when animation starts

This change removes a delayed scene snap when activity launch animation
starts. Instead it attemps to snap immediately when the animation ends.

Test: atest CommunalTransitionAnimatorControllerTest
Fix: 443213605
Bug: 330672236
Flag: EXEMPT BUGFIX
Change-Id: I6e2a0b73b356723b3034ba164021a085c6a84bb0