Remove js-toggle classes

app/views/shared/milestones/_deprecation_message.html.haml

-.milestone-deprecation-message.prepend-top-default.js-toggle-container
+.milestone-deprecation-message.prepend-top-default
   = image_tag 'illustrations/milestone_removing-page.svg', class: 'append-right-default'
   .inline.vertical-align-middle.text-container
     %strong This page will be removed in a future release.
     %p.append-bottom-default.prepend-top-5
       Use group milestones to manage issues from multiple projects in the same milestone.
       %br
-      = button_tag 'Promote these project milestones into a group milestone.', class: 'btn-link js-toggle-button'
+      = button_tag 'Promote these project milestones into a group milestone.', class: 'btn-blank'
 
-    .popup.js-toggle-content.hide
+    .popup.hide
       .body
         %ol.instructions-list
           %li