UX: Display site settings shortcut for poll and discourse-nginx-performance-report.

https://meta.discourse.org/t/improving-admin-plugins/84585/29?u=tgxworld

lib/plugin/instance.rb

@@ -493,6 +493,14 @@ JS
     PluginGem.load(path, name, version, opts)
   end
 
+  def enabled_site_setting_filter(filter = nil)
+    if filter
+      @enabled_setting_filter = filter
+    else
+      @enabled_setting_filter
+    end
+  end
+
   def enabled_site_setting(setting = nil)
     if setting
       @enabled_site_setting = setting