Fix help campo extra data

EventListener/SonataAdminConfigureListener.php

@@ -29,10 +29,9 @@ class SonataAdminConfigureListener
     {
         $formMapper = $event->getMapper();
         if ($formMapper->has('extraData')) {
-            $ed = $formMapper->getFormBuilder()->get('extraData');
-            $ed->getOptions()['required'] = false;
-            $ed->getOptions()['label'] = $this->trans('form.label_extra_data');
-            $ed->getOptions()['help'] = $this->trans('help.json_format');
+            $formMapper->addHelp('extraData', $this->trans('help.json_format'));
+            $extraDataField = $formMapper->get('extraData');
+            $extraDataField->setRequired(false);
         }
     }