Use FooterPreference in xml explicitly

Removed the FooterPreferenceMixin from the DeviceAdminSettings page.

Fixes: 140015273
Test: manual test
Test: make RunSettingsRoboTests ROBOTEST_FILTER=com.android.settings.applications
Change-Id: I91c10946ae35f9a5cde30399e231dbc8a1481b23

src/com/android/settings/applications/specialaccess/deviceadmin/DeviceAdminSettings.java

@@ -37,13 +37,6 @@ public class DeviceAdminSettings extends DashboardFragment {
         return SettingsEnums.DEVICE_ADMIN_SETTINGS;
     }
 
-    @Override
-    public void onAttach(Context context) {
-        super.onAttach(context);
-        use(DeviceAdminListPreferenceController.class).setFooterPreferenceMixin(
-                mFooterPreferenceMixin);
-    }
-
     @Override
     protected int getPreferenceScreenResId() {
         return R.xml.device_admin_settings;