Checkmk Werk 12668: API folder_config: fixing the show endpoint which did not work for the root folder

ID: 12668 Title: API folder_config: fixing the show endpoint which did not work for the root folder Component: Core & setup Level: 1 Class: Bug fix Version: 2.1.0i1 In the previous version, it was not possible for the get the root folder through the show endpoint. This werk fixes this behavior.