Fix removing all port groups (#14253)

* Fix removing all port groups

* Make backend work in the situation where this endpoint is used for more than just this setting change
change event is called multiple times when select2 is cleared (once for each item)
prevent duplicate backend calls
Remove no default Port Group item

app/Http/Controllers/Select/PortGroupController.php

@@ -39,19 +39,6 @@ class PortGroupController extends SelectController
         return PortGroup::hasAccess($request->user())->select(['id', 'name']);
     }
 
-    protected function formatResponse($paginator)
-    {
-        // prepend the default group, unless filtered out
-        if ($this->includeGeneral()) {
-            $general = new PortGroup;
-            $general->id = 0;
-            $general->name = 'no default Port Group';
-            $paginator->prepend($general);
-        }
-
-        return parent::formatResponse($paginator);
-    }
-
     /**
      * @param  PortGroup  $port_group
      */