Defer resetting the animation controller and targets on cancel

- In the case where the recents animation is canceled while the running
  window animation is running, we invalidate the handler, and force end
  the window animation, which results in the end target being calculated
  and transitioned to.  Because the handlers can still reference the
  animation controller at this point (even though the calls will be
  no-ops since it was canceled), we should not reset the vars until the
  state has been updated.

Bug: 145641576

Change-Id: I5a660026fabb5beb0c45dffeeb4cb4feef5dec30