Update flyout content during animation

This change translates the content of the flyout according
to the progress of the animation. Adding an outline provider
allows clipping the content to the bounds of the animating
background.

Also animate the color of the background.

Demo:
on left - http://recall/-/bJtug1HhvXkkeA4MQvIaiP/cH2EK0FiD92dykhLkLeyh1
on right - http://recall/-/bJtug1HhvXkkeA4MQvIaiP/btpcter79rAlcavd4xxHu7

Flag: com.android.wm.shell.enable_bubble_bar
Bug: 277815200
Test: atest BubbleBarFlyoutViewScreenshotTest
Test: atest BubbleBarFlyoutControllerTest

Change-Id: Id142af2041410c0570759a360146d5e084411cc1