Remove gap between popup items

- Unround interior corners
- Update colors (shortcuts are gray when next to
  notifications, notifications always white)
- Clean up animation to animate entire popup with
  simple reveal instead of individual items
  animating with reveal and icon scale

Bug: 35766387
Bug: 36110804
Change-Id: I33685d53e2db3904731676123dc230be4dabb5d4