Load ci_bundle javascripts in MWBS partial

app/views/projects/merge_requests/widget/open/_merge_when_build_succeeds.html.haml

+- content_for :page_specific_javascripts do
+  = page_specific_javascript_tag('merge_request_widget/ci_bundle.js')
+
 %h4
   Set by #{link_to_member(@project, @merge_request.merge_user, avatar: true)}
   to be merged automatically when the pipeline succeeds.