End transitions when receiving merge request

The default behavior (if nothing is done) for a merge request
is to let the animation continue and queue up the incoming animation
to start once the current one has finished.

This is maybe the "smoothest" default; however, it is not
responsive for the user. So, instead, go through and, where
appropriate, make animations "jump-to-end" when they receive
a merge request. This way the user will see the new animation
start immediately after they perform an action. There is
technically a "jump" in the animation, but it seems like the
responsiveness is preferable and the jumps aren't super
noticable anyways. This is also how legacy transitions works
so it's not a behavior change.

Bug: 236309064
Test: interrupt animations with other transitions and observe.
      Example: launch an app and then go "back" before it finishes
      animating.
Change-Id: I4a76e7efe2c610b22f3fe97b0bd3ab692a01be08