Working on sorting dropdown commentables

lms/templates/discussion/_filter_dropdown.html

@@ -2,6 +2,7 @@
 <%! import json %>
 
 <%def name="render_dropdown(map)">
+    ${map["children"].sort()}
     % for child in map["children"]:
         % if child in map["entries"]:
             ${render_entry(map["entries"], child)}