FIX: Only refresh the review count when the user can see the review queue. (#12453)

We currently make an AJAX request every time someone opens the hamburger menu, resulting in a forbidden response when a user can't see the review queue.

app/serializers/current_user_serializer.rb

@@ -52,6 +52,7 @@ class CurrentUserSerializer < BasicUserSerializer
              :skip_new_user_tips,
              :do_not_disturb_until,
              :has_topic_draft,
+             :can_review
 
   def groups
     object.visible_groups.pluck(:id, :name).map { |id, name| { id: id, name: name } }
@@ -212,6 +213,10 @@ class CurrentUserSerializer < BasicUserSerializer
     Reviewable.list_for(object).count
   end
 
+  def can_review
+    scope.can_see_review_queue?
+  end
+
   def mailing_list_mode
     object.user_option.mailing_list_mode
   end