Add ee only comment to boards_bundle.js ee imports

app/assets/javascripts/boards/boards_bundle.js

@@ -25,6 +25,7 @@ import './components/new_list_dropdown';
 import './components/modal/index';
 import '../vue_shared/vue_resource_interceptor';
 
+// EE only
 import './components/boards_selector';
 import collapseIcon from './icons/fullscreen_collapse.svg';
 import expandIcon from './icons/fullscreen_expand.svg';