Add notification dots and popup menu notification support to the taskbar.

- Added support for notification dots
- Added support for notifications in popup menu
- Added support for dismissing notifications from the popup menu

Bug: 198438631
Test: long pressed launcher and taskbar icons, clicked notifications, clicked shortcuts
Change-Id: I7c981e60a82b4d6ce28332d804bbbfb5eb89c6a8

quickstep/src/com/android/launcher3/taskbar/TaskbarControllers.java

@@ -92,6 +92,7 @@ public class TaskbarControllers {
         stashedHandleViewController.init(this);
         taskbarStashController.init(this, sharedState);
         taskbarEduController.init(this);
+        taskbarPopupController.init(this);
     }
 
     /**
@@ -107,5 +108,6 @@ public class TaskbarControllers {
         taskbarViewController.onDestroy();
         stashedHandleViewController.onDestroy();
         taskbarAutohideSuspendController.onDestroy();
+        taskbarPopupController.onDestroy();
     }
 }