optional chaining to prevent errors

assets/javascripts/discourse/connectors/category-custom-settings/create-topic-wizard.js.es6

@@ -8,9 +8,10 @@ export default {
         component.set("wizardList", result);
       })
       .catch(popupAjaxError);
+      attrs
     component.set(
       "wizardListVal",
-      attrs.category.custom_fields.create_topic_wizard
+      attrs?.category?.custom_fields?.create_topic_wizard
     );
   },