Make sure the fragment manager is passed to BubblePreferenceController

This wasn't being set always / at least for the app specific page.
This CL ensures it is & makes it so that there is only 1 constructor.

Fixes: 132864244
Test: make -j40 RunSettingsRoboTests ROBOTEST_FILTER=Bubble
Change-Id: I9c422e75583b3091d1571cfb8cc43ec49b801599

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

@@ -61,7 +61,10 @@ public class AppBubbleNotificationSettings extends NotificationSettingsBase impl
             Context context, AppBubbleNotificationSettings fragment) {
         List<NotificationPreferenceController> controllers = new ArrayList<>();
         controllers.add(new HeaderPreferenceController(context, fragment));
-        controllers.add(new BubblePreferenceController(context, new NotificationBackend()));
+        controllers.add(new BubblePreferenceController(context, fragment != null
+                ? fragment.getChildFragmentManager()
+                : null,
+                new NotificationBackend()));
         return controllers;
     }