ensure jQuery is loaded before running pageless on user_notes page

refs: CNVS-28781

I don't think this would have been a problem in production
but locally, jquery ($) was not loaded yet when
it tried to run this

test plan:
load http://c.dev/users/1/user_notes
it should not say "$ is not defined" in dev console

Change-Id: I5adcef12d6e6cee64431b6ff00a0856085ac2841
Reviewed-on: https://gerrit.instructure.com/84835
Tested-by: Jenkins
QA-Review: Jeremy Putnam <jeremyp@instructure.com>
Reviewed-by: Simon Williams <simon@instructure.com>
Product-Review: Ryan Shaw <ryan@instructure.com>

app/helpers/user_notes_helper.rb

@@ -28,6 +28,10 @@ module UserNotesHelper
 </div>'
     }
     
-    javascript_tag("$('#user_note_list').pageless(#{opts.to_json});")
+    javascript_tag("
+      require(['jquery', 'vendor/jquery.pageless'], function(){
+        $('#user_note_list').pageless(#{opts.to_json});
+      });
+    ")
   end
 end