Retrieve help URL

Fixes: 118644802

Test: Help page is seen
Change-Id: Ib89d21ce5027f9ca9c3b6709a9a1301f988a0675

src/com/android/settings/biometrics/face/FaceSettings.java

@@ -228,6 +228,11 @@ public class FaceSettings extends DashboardFragment {
         }
     }
 
+    @Override
+    public int getHelpResource() {
+        return R.string.help_url_face;
+    }
+
     @Override
     protected List<AbstractPreferenceController> createPreferenceControllers(Context context) {
         if (!isAvailable(context)) {