Add divider line below "see all apps" preference

- and increase the tile limit by 1 to accomodate the divider.

Change-Id: I94cbf47fd987a6ff4c4fabcc3124fae1f0438876
Fix: 63906012
Test: make RunSettingsRoboTests
(cherry picked from commit 6cd558e595)

src/com/android/settings/applications/AppAndNotificationDashboardFragment.java

@@ -50,7 +50,7 @@ public class AppAndNotificationDashboardFragment extends DashboardFragment {
     @Override
     public void onAttach(Context context) {
         super.onAttach(context);
-        mProgressiveDisclosureMixin.setTileLimit(3);
+        mProgressiveDisclosureMixin.setTileLimit(4);
     }
 
     @Override