Add help url placeholders for new pages

Bug: 38412798
Test: visual
Change-Id: I4ede523cb13790ea05309279f80a778b2086f850

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

@@ -53,6 +53,11 @@ public class AppAndNotificationDashboardFragment extends DashboardFragment {
         mProgressiveDisclosureMixin.setTileLimit(3);
     }
 
+    @Override
+    protected int getHelpResource() {
+        return R.string.help_url_apps_and_notifications;
+    }
+
     @Override
     protected int getPreferenceScreenResId() {
         return R.xml.app_and_notification;