Clear recents animation controllers and recents animation snapshots synchronously.

Clearing the recents animation controller synchronously immediately after posting a screenshot cleanup was making it almost impossible to cleanup the screenshot when cancelling the recents animation. Moved  the recents animation controller clearing to run synchronously with cleaning up the screenshot.

Bug: 223498680
Test: manually with 3 button mode.
Change-Id: I6af5bd4525976eb6956d0466dceae1787b3b84d8