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/applications/appinfo/AppInfoDashboardFragment.java

@@ -44,6 +44,8 @@ import com.android.settings.R;
 import com.android.settings.SettingsActivity;
 import com.android.settings.SettingsPreferenceFragment;
 import com.android.settings.applications.manageapplications.ManageApplications;
+import com.android.settings.applications.specialaccess.pictureinpicture
+        .PictureInPictureDetailPreferenceController;
 import com.android.settings.core.SubSettingLauncher;
 import com.android.settings.dashboard.DashboardFragment;
 import com.android.settingslib.RestrictedLockUtils;
@@ -281,7 +283,7 @@ public class AppInfoDashboardFragment extends DashboardFragment
         mAppEntry = appEntry;
     }
 
-    PackageInfo getPackageInfo() {
+    public PackageInfo getPackageInfo() {
         return mPackageInfo;
     }