Migrate ownership when deleting user not working #4124

Describe the Bug

When deleting an (LDAP) user from within bookstack the ownership migration is not working.
After deletion the migrated pages/books/chapters have no owner.

Steps to Reproduce

1. Select an user from the user list in settings.
2. Click delete.
3. Choose an other user from the dropdown "Migrate Ownership".
4. Click confirm.

Expected Behaviour

The migrated pages are owned by the selected user.

Screenshots or Additional Context

No response

Browser Details

No response

Exact BookStack Version

v23.02.1

PHP Version

8.1

Hosting Environment

Alpine-based Docker setup inspired by https://github.com/linuxserver/docker-bookstack