Merge branch 'group-wikis-disable-git-access' into 'master'

Disable "Clone repository" link for group wikis

See merge request gitlab-org/gitlab!44564

app/views/shared/wikis/_sidebar.html.haml

@@ -4,6 +4,7 @@
       %a.gutter-toggle.float-right.d-block.d-sm-block.d-md-none.js-sidebar-wiki-toggle{ href: "#" }
         = sprite_icon('chevron-double-lg-right', css_class: 'gl-icon')
 
+      - if @wiki.container.is_a?(Project)
         - git_access_url = wiki_path(@wiki, action: :git_access)
         = link_to git_access_url, class: active_nav_link?(path: 'wikis#git_access') ? 'active' : '', data: { qa_selector: 'clone_repository_link' } do
           = sprite_icon('download', css_class: 'gl-mr-2')