Tidy up epic promotion buttons

ee/app/views/shared/promotions/_promote_epics.html.haml

@@ -20,9 +20,9 @@
           %p
             = s_('Promotions|Epics let you manage your portfolio of projects more efficiently and with less effort by tracking groups of issues that share a theme, across projects and milestones.')
             = link_to s_('Read more'), 'https://docs.gitlab.com/ee/user/group/epics/', class: 'btn-link', target: '_blank'
-          %div
+          .gl-display-flex.gl-flex-wrap
             = render 'shared/promotions/promotion_link_project', short_form: true
-            = link_to s_("Promotions|Don't show me this again"), '#', class: ['btn', 'js-close', 'js-close-callout']
+            = link_to s_("Promotions|Don't show me this again"), '#', class: 'btn js-close js-close-callout gl-mt-2'
 
     .hide-collapsed
       = s_('Promotions|This feature is locked.')