Fix visibility of notification footer divider

Now it is only visible when the notification footer is present,
instead of always being visible.

Change-Id: Ie85ff31918901115cdfe55b36e75aa80b43e7b13

src/com/android/launcher3/notification/NotificationFooterLayout.java

@@ -205,6 +205,7 @@ public class NotificationFooterLayout extends FrameLayout {
                 collapseFooter.addListener(new AnimatorListenerAdapter() {
                     @Override
                     public void onAnimationEnd(Animator animation) {
+                        ((ViewGroup) getParent()).findViewById(R.id.divider).setVisibility(GONE);
                         ((ViewGroup) getParent()).removeView(NotificationFooterLayout.this);
                     }
                 });