added fallback value

utils/validator.ts

@@ -161,7 +161,7 @@ export default {
    * @param {string} entityName - the entity name
    * @returns {(visibility: Visibility) => boolean | string} a function that validates the visibility of an entity
    */
-  validateVisibility (groups: IPermissionGroup[], entityName: string, persistentIdentifier: string | null): (visibility: Visibility) => boolean | string {
+  validateVisibility (groups: IPermissionGroup[], entityName: string, persistentIdentifier: string | null = null): (visibility: Visibility) => boolean | string {
     return function (visibility: Visibility) {
       if (visibility === Visibility.Private && persistentIdentifier) {
         return `You are not allowed to set the visibility to private when the ${entityName} has a persistent identifier (PID).`