Set bubble bar alpha to 0 and collapse if it bubbles are hidden

Only set bubble bar alpha to 0 and mark it collapsed when bubbles are
hidden.
When bubble bar should be hidden due to system ui state, only update
visibility.

Bug: 324068295
Flag: ACONFIG com.android.wm.shell.enable_bubble_bar DEVELOPMENT
Test: trigger a buble from bubbles test app
  - swipe to home screen
  - observe bubble bar is shown
  - swipe notification shade down and away again
  - observe bubble bar is hidden when shade is open, and shown when
    closed
  - expand bubble bar
  - repeat swipe shade down and away, observe expanded bubble is hidden
    while shade is open and bubble is expanded when shade is swiped away
Change-Id: Icc717ab250061f14f02a558eb9f7301fdc08c5c7

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

@@ -233,6 +233,10 @@ public class BubbleBarViewController {
         if (mHiddenForNoBubbles != hidden) {
             mHiddenForNoBubbles = hidden;
             updateVisibilityForStateChange();
+            if (hidden) {
+                mBarView.setAlpha(0);
+                mBarView.setExpanded(false);
+            }
             mActivity.bubbleBarVisibilityChanged(!hidden);
         }
     }
@@ -259,8 +263,6 @@ public class BubbleBarViewController {
             mBarView.setVisibility(VISIBLE);
         } else {
             mBarView.setVisibility(INVISIBLE);
-            mBarView.setAlpha(0);
-            mBarView.setExpanded(false);
         }
     }