RfCs: Enable admin menu for teachers

We allow any teacher to view the admin menu within RfCs. The specific actions might differ, based on the membership of the RfC author and the teacher in the respective study groups. Nevertheless, this quick fix allows more users to perform content moderation tasks.

Author: MrSerth

app/views/request_for_comments/show.html.slim

@@ -66,7 +66,7 @@
                   span.fa-solid.fa-chevron-down.collapse-button
                   pre = testrun.log || t('request_for_comments.no_output')
 
-    - if current_user.admin? && user.is_a?(ExternalUser)
+    - if current_user.teacher? && user.is_a?(ExternalUser)
       = render('admin_menu')
 
     hr