Fix formFieldsApi resolution in useCustomFieldExtensions hook

Signed-off-by: Tim Hansen <timbonicush@spotify.com>

.changeset/rich-penguins-stare.md

@@ -0,0 +1,5 @@
+---
+'@backstage/plugin-scaffolder-react': patch
+---
+
+Fixed scaffolder form fields not resolving correctly in the `useCustomFieldExtensions` hook.

plugins/scaffolder-react/src/hooks/useCustomFieldExtensions.ts

@@ -34,11 +34,11 @@ export const useCustomFieldExtensions = <
 ) => {
   // Get custom fields created with FormFieldBlueprint
   const formFieldsApi = useApi(formFieldsApiRef);
-  const [{ result: blueprintFields }, methods] = useAsync(
-    formFieldsApi.getFormFields,
+  const [{ result: blueprintFields }, { execute }] = useAsync(
+    () => formFieldsApi.getFormFields(),
     [],
   );
-  useMountEffect(methods.execute);
+  useMountEffect(execute);
 
   // Get custom fields created with ScaffolderFieldExtensions
   const outletFields = useElementFilter(outlet, elements =>