1472 dont highlight text when learners are doing listening activity (#1482)

* fix: don't highlight words while doing hwl activity

* fix: don't sort activity choices after the fact

lib/pangea/toolbar/widgets/practice_activity/multiple_choice_activity.dart

@@ -188,7 +188,6 @@ class MultipleChoiceActivityState extends State<MultipleChoiceActivity> {
         ),
       );
     }
-    choices.sort((a, b) => a.text.length.compareTo(b.text.length));
     return choices;
   }