Fix not displaying "Allow restricted settings"

"Allow restricted settings" is missed from SPA, added to SPA to fix this
issue.

Also make the system call in app info more options async to improve
performance.

Fix: 273678047
Test: Unit test
Test: By the following steps,
1. Install an app with accessibility feature from Chrome
2. Go Accessibility page and click on the disabled grey app
3. Go to the app info page, click more options
4. Make sure "Allow restricted settings" is displayed

Change-Id: I4adbe2335a32e6a7c4ebe155715684d768e5d1ef

src/com/android/settings/applications/appinfo/AppInfoDashboardFragment.java

@@ -437,7 +437,8 @@ public class AppInfoDashboardFragment extends DashboardFragment
         }
     }
 
-    private static void showLockScreen(Context context, Runnable successRunnable) {
+    /** Shows the lock screen if the keyguard is secured. */
+    public static void showLockScreen(Context context, Runnable successRunnable) {
         final KeyguardManager keyguardManager = context.getSystemService(
                 KeyguardManager.class);