New switch animation for bubble bar bubbles

Create a new animation for switching between bubbles. Slide the expanded
view in from the edge of the screen, on top of the existing bubble.
Keep the existing animation for expanding/collapsing the bar.

Bug: 276747288
Test: manual
Flag: com.android.wm.shell.enable_bubble_bar
Change-Id: I7b2a1631bda01dfb53f47d6aac1ba01729e4c564