Add highlight menu keys for all toggle pref controllers and custom slices

Bug: 204695404
Test: manual, robotest build pass, unit
Change-Id: Iad2e28ada8ddb766ffa7eff2c8dc581250cbd6f8

src/com/android/settings/notification/SpatialAudioPreferenceController.java

@@ -20,6 +20,7 @@ import android.content.Context;
 import android.media.AudioManager;
 import android.media.Spatializer;
 
+import com.android.settings.R;
 import com.android.settings.core.TogglePreferenceController;
 
 /**
@@ -53,4 +54,9 @@ public class SpatialAudioPreferenceController extends TogglePreferenceController
         mSpatializer.setEnabled(isChecked);
         return isChecked == isChecked();
     }
+
+    @Override
+    public int getSliceHighlightMenuRes() {
+        return R.string.menu_key_notifications;
+    }
 }