[Settings] Support getSystemService(Class<T>)

Add getSystemService(Class<T>) to align the capability with framework
part.

This is a back port from aosp/1639943, aosp/1645152 and aosp/1648047

Bug: 179640862
Test: local
Change-Id: I035db55a71f94000ca35f8d71f03c19208423c73

src/com/android/settings/wifi/ChangeWifiStateDetails.java

@@ -49,7 +49,7 @@ public class ChangeWifiStateDetails extends AppInfoWithHeader
         super.onCreate(savedInstanceState);
         final Context context = getActivity();
         mAppBridge = new AppStateChangeWifiStateBridge(context, mState, null);
-        mAppOpsManager = (AppOpsManager) context.getSystemService(Context.APP_OPS_SERVICE);
+        mAppOpsManager = context.getSystemService(AppOpsManager.class);
 
         // find preferences
         addPreferencesFromResource(R.xml.change_wifi_state_details);