fix(mui): validation error invalid type declaration

Author: Hyperkid123

packages/mui-component-mapper/src/validation-error/validation-error.d.ts

@@ -1,5 +1,5 @@
 import { Meta } from "@data-driven-forms/react-form-renderer";
 
-export type validationError = (meta: Meta<any>, validateOnMount?: boolean) => boolean | any | undefined;
+export function validationError(meta: Meta<any>, validateOnMount?: boolean): boolean | any | undefined;
 
 export default validationError;