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/gestures/LongPressPowerButtonPreferenceController.java

@@ -120,6 +120,11 @@ public class LongPressPowerButtonPreferenceController extends TogglePreferenceCo
         return false;
     }
 
+    @Override
+    public int getSliceHighlightMenuRes() {
+        return R.string.menu_key_system;
+    }
+
     private void refreshStateDisplay() {
         if (mAssistSwitch != null) {
             mAssistSwitch.setSummary(getSummary());