Reset preview only after transition completed (2/2)

This is to solve an issue of the children aniamtion getting interrupted
by their parent layout is also animating.

The reset will trigger the animation of the children UI components and
it can be interrupted by the parent floating sheet layout anmiation
down.

Test: Manually tested. See bug.
Fixes: 383747200
Flag: com.android.systemui.shared.new_customization_picker_ui
Change-Id: I224bb45d836466ba80bf958b842c85b466e91f25