Add settings for notification bubbling

Globally, as well as at the app and channel level

Test: atest
Bug: 123543052
Change-Id: I1668b592c5d175d77d6a38f35e7576d641175d44

src/com/android/settings/notification/BadgePreferenceController.java

@@ -60,7 +60,7 @@ public class BadgePreferenceController extends NotificationPreferenceController
             if (isDefaultChannel()) {
                 return true;
             } else {
-                return mAppRow.showBadge;
+                return mAppRow == null ? false : mAppRow.showBadge;
             }
         }
         return true;