Scroll recents side to side during swipe up from an app

- Swiping straight up and down works the same as before.
- We dispatch the MotionEvents to RecentsView so that it scrolls if you
  swipe side to side as you swipe up.
- As RecentsView scrolls, we offset the window to match the position of
  the first task
- If you scroll or fling towards the previous app, it will settle on it
  and launch it.

Bug: 111699315
Change-Id: I1ff160cfc3ca66302a2506d18a4788015de75b94