Checkmk Werk 15167: folder_config: fix querying a folder with invalid time in network scan option

ID: 15167 Title: folder_config: fix querying a folder with invalid time in network scan option Component: REST API Level: 1 Class: Bug fix Version: 2.2.0i1 Prior to this werk, the REST-API raised an error when the user tried to query a folder config which had the network scan option configured with 24:00 in one its time ranges. This werk fixes this behaviour.