Describe the bug
POST requests on fields/group return a 500 error

To Reproduce
Steps to reproduce the behavior:

1. Go to your postman collection
2. Click on send POST request of any fields/groups
3. Scroll down to response
4. See 500 error

Expected behavior
field groups created via the Joomla! 4 Web Service POST endpoints with status 200

Screenshots
none

Desktop (please complete the following information):

• OS: Ubuntu 20.04
• Browser: Chrome
• Web Server: Nginx
• Joomla: 4.0.5
• Php 8.1.0

Additional context
none