Verify filtering for `call_hook_script`
The stadtgestalten.org instance calls the call_hook_script
task way too often:
# journalctl -xu grouprise-tasks | grep -c "Executing grouprise.features.groups.signals.call_hook_script"
68817
The log contains three weeks of messages. The hook should only be called for every creation or deletion event of a group. Probably we are receiving too many events here.