Make the group name field show up as required to screenreaders

Fixes CNVS-20968

Test plan:
 - When viewing a group set, click "+ Group"
 - With the screenreader turned on, focus the name field
 - Ensure that your screenreader notes that the field is required

Change-Id: Ic9892a634515bd40bf26b26bfd35e6586fc0221c
Reviewed-on: https://gerrit.instructure.com/56670
Tested-by: Jenkins
Reviewed-by: Matthew Wheeler <mwheeler@instructure.com>
QA-Review: Steven Shepherd <sshepherd@instructure.com>
Product-Review: Alex Boyd <aboyd@instructure.com>

Author: javawizard

app/views/jst/groups/manage/groupEdit.handlebars

@@ -1,7 +1,7 @@
 <div class="control-group">
   <label class="control-label" for="group_name">{{#t "group_name"}}Group Name{{/t}}</label>
   <div class="controls">
-    <input type="text" id="group_name" name='name' value="{{name}}"
+    <input type="text" id="group_name" name='name' value="{{name}}" aria-required="true"
            placeholder="{{#t "group_name"}}Group Name{{/t}}">
   </div>
 </div>