[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/UseOpenWifiPreferenceController.java

@@ -51,7 +51,7 @@ public class UseOpenWifiPreferenceController extends TogglePreferenceController
         super(context, KEY_USE_OPEN_WIFI_AUTOMATICALLY);
         mContentResolver = context.getContentResolver();
         mNetworkScoreManager =
-                (NetworkScoreManager) context.getSystemService(Context.NETWORK_SCORE_SERVICE);
+                context.getSystemService(NetworkScoreManager.class);
         mSettingObserver = new SettingObserver();
         updateEnableUseWifiComponentName();
         checkForFeatureSupportedScorers();