[2.3.0] Checkmk Werk 17119 created: parent_scan: resolve failing parent scan background job

[//]: # (werk v2) # parent_scan: resolve failing parent scan background job key | value ---------- | --- date | 2024-07-02T12:39:27+00:00 version | 2.3.0p9 class | fix edition | cre component | rest-api level | 1 compatible | yes The REST API endpoint to initiate the parent scan background job returned a 204 status code, which theoretically is correct. However, the started background job failed immediately due to an invalid Python syntax concerning the involving requested hosts. This werk fixes the issue.