Merge branch 'ee-10428-cluster-sidebar' into 'master'

EE: Removes EE differences for clusters/_sidebar.html.haml

See merge request gitlab-org/gitlab-ee!10233

app/views/clusters/clusters/_sidebar.html.haml

-- autodevops_help_url = help_page_path('topics/autodevops/index.md', anchor: 'using-multiple-kubernetes-clusters-premium')
-- help_link_start = '<a href="%{url}" target="_blank" rel="noopener noreferrer">'.html_safe
-- help_link_end = '</a>'.html_safe
 %h4.prepend-top-0
   = s_('ClusterIntegration|Add a Kubernetes cluster integration')
 %p
   = clusterable.sidebar_text
 %p
   = clusterable.learn_more_link
-%p
-  = s_('ClusterIntegration|If you are setting up multiple clusters and are using Auto DevOps, %{help_link_start}read this first%{help_link_end}.').html_safe % { help_link_start: help_link_start % { url: autodevops_help_url }, help_link_end: help_link_end }
+
+= render_if_exists 'clusters/multiple_clusters_message'

ee/app/views/clusters/_multiple_clusters_message.html.haml

+- autodevops_help_url = help_page_path('topics/autodevops/index.md', anchor: 'using-multiple-kubernetes-clusters-premium')
+- help_link_start = '<a href="%{url}" target="_blank" rel="noopener noreferrer">'.html_safe
+- help_link_end = '</a>'.html_safe
+
+%p
+  = s_('ClusterIntegration|If you are setting up multiple clusters and are using Auto DevOps, %{help_link_start}read this first%{help_link_end}.').html_safe % { help_link_start: help_link_start % { url: autodevops_help_url }, help_link_end: help_link_end }