Show navigation line separator when instance metrics is disabled

app/helpers/nav_helper.rb

@@ -19,10 +19,7 @@ module NavHelper
   end
 
   def page_gutter_class
-    if current_path?('merge_requests#show') ||
+    if page_has_markdown?
-        current_path?('projects/merge_requests/conflicts#show') ||
-        current_path?('issues#show') ||
-        current_path?('milestones#show')
 
       if cookies[:collapsed_gutter] == 'true'
         %w[page-gutter right-sidebar-collapsed]
@@ -50,6 +47,17 @@ module NavHelper
     class_names
   end
 
+  def show_separator?
+    Gitlab::Sherlock.enabled? || can?(current_user, :read_instance_statistics)
+  end
+
+  def page_has_markdown?
+    current_path?('merge_requests#show') ||
+      current_path?('projects/merge_requests/conflicts#show') ||
+      current_path?('issues#show') ||
+      current_path?('milestones#show')
+  end
+
   private
 
   def get_header_links

app/views/layouts/nav/_dashboard.html.haml

@@ -64,7 +64,7 @@
         = link_to '#', class: 'dashboard-shortcuts-web-ide', title: _('Web IDE') do
           = _('Web IDE')
 
-  - if Gitlab::Sherlock.enabled? || can?(current_user, :read_instance_statistics)
+  - if show_separator?
     %li.line-separator.d-none.d-sm-block
   = render_if_exists 'dashboard/operations/nav_link'
   - if can?(current_user, :read_instance_statistics)