changelog/10.9.0_2021-12-20/39532
Bugfix: Group select in user create panel allows empty and pre-existing groups
Before this change, the admin could create groups with empty name or multiple
times with the same name.
This has been fixed with this change.
https://github.com/owncloud/core/pull/39532
https://github.com/owncloud/enterprise/issues/4890