Add a few pages to search index.

- Data saver
- A few special permission access pages
   - Picture-in-picture
   - Premium sms
   - do not disturb access
- And a unrelated cleanup: move EmptyTextFragment from
  notification/ to widget/

Bug: 70720645
Test: robotests
Change-Id: I6a87f712bf81f9fd32fa9a3826fba851ca748409

src/com/android/settings/datausage/UnrestrictedDataAccessPreferenceController.java

@@ -21,6 +21,7 @@ import android.os.UserHandle;
 
 import com.android.internal.annotations.VisibleForTesting;
 import com.android.internal.logging.nano.MetricsProto.MetricsEvent;
+import com.android.settings.R;
 import com.android.settings.applications.AppStateBaseBridge;
 import com.android.settings.core.BasePreferenceController;
 import com.android.settings.dashboard.DashboardFragment;
@@ -83,7 +84,9 @@ public class UnrestrictedDataAccessPreferenceController extends BasePreferenceCo
 
     @Override
     public int getAvailabilityStatus() {
-        return AVAILABLE;
+        return mContext.getResources().getBoolean(R.bool.config_show_data_saver)
+                ? AVAILABLE_UNSEARCHABLE
+                : UNSUPPORTED_ON_DEVICE;
     }
 
     @Override