Allow for continuous scrolling to previous tasks

Starting a new touch interaction on the nav bar while going to a new task
cancels that animation to allow for continuous scrolling.

Specifically, the new interaction still creates a new touch consumer and
WindowTransformSwipeHandler, but reuses the previous RecentsAnimationState
in order to defer finishing it.

Bug: 111926330
Change-Id: Ia4f5f8dbb2b3ae70791676f1e3e5ce84deb22f74