Add show_footer parameter for ability to hide footer

app/views/shared/issuable/_label_dropdown.html.haml

@@ -20,5 +20,6 @@
   .dropdown-menu.dropdown-select.dropdown-menu-paging.dropdown-menu-labels.dropdown-menu-selectable
     = render partial: "shared/issuable/label_page_default", locals: { title: "Filter by label" }
     - if can? current_user, :admin_label, @project and @project
+    = render partial: "shared/issuable/label_page_default", locals: { title: "Filter by label", show_footer: show_footer }
       = render partial: "shared/issuable/label_page_create"
     = dropdown_loading

app/views/shared/issuable/_label_page_default.html.haml

 - title = local_assigns.fetch(:title, 'Assign labels')
+- show_footer = local_assigns.fetch(:show_footer, true)
 - filter_placeholder = local_assigns.fetch(:filter_placeholder, 'Search labels')
 .dropdown-page-one
   = dropdown_title(title)
   = dropdown_filter(filter_placeholder)
   = dropdown_content
-  - if @project
+  - if @project and show_footer
     = dropdown_footer do
       %ul.dropdown-footer-list
         - if can? current_user, :admin_label, @project