Animate the bubble bar to show new bubble

This change updates that animation that plays when a new bubble notification is received. We now animate the entire bubble bar rather than the individual bubble.

Demo: http://recall/-/bJtug1HhvXkkeA4MQvIaiP/dwbsZJZlqLwJ2IG7RfJZ7c

Flag: ACONFIG com.android.wm.shell.enable_bubble_bar DEVELOPMENT
Bug: 280605846
Test: atest BubbleBarViewAnimatorTest
Change-Id: I2dc58ad61b880d76c9eefa462c3aee4e8bbb3584

quickstep/src/com/android/launcher3/taskbar/bubbles/BubbleStashedHandleViewController.java

@@ -251,11 +251,6 @@ public class BubbleStashedHandleViewController {
         return mStashedHandleAlpha;
     }
 
-    /** Returns the x position of the center of the stashed handle. */
-    public float getStashedHandleCenterX() {
-        return mStashedHandleBounds.exactCenterX();
-    }
-
     /**
      * Creates and returns an Animator that updates the stashed handle  shape and size.
      * When stashed, the shape is a thin rounded pill. When unstashed, the shape morphs into