Return getMetricsCategory() for each new page hearing aid and flash notifications in android U

Bug: 262839191
Test: manual test
Change-Id: I066f49a2537b798132b484f6eff0d0314a164138

src/com/android/settings/accessibility/FlashNotificationsPreferenceFragment.java

@@ -16,6 +16,7 @@
 
 package com.android.settings.accessibility;
 
+import android.app.settings.SettingsEnums;
 import android.content.Context;
 
 import com.android.settings.R;
@@ -41,8 +42,7 @@ public class FlashNotificationsPreferenceFragment extends DashboardFragment {
 
     @Override
     public int getMetricsCategory() {
-        // TODO: Flash notifications have to add SettingsEnums.
-        return 0;
+        return SettingsEnums.FLASH_NOTIFICATION_SETTINGS;
     }
 
     @Override