Remove Element worker version ID attributes from the API

Please remove the following fields from the API:

CreateDatasetElement
- element.worker_version_id in the response
CreateElement
- worker_version ForbiddenField in the request body
- worker_version UUID in the response
ListDatasetElements
- element.worker_version_id in the response
ListElementChildren
- worker_version_id in the response
ListElementParents
- worker_version_id in the response
ListElements
- worker_version_id in the response
ListSelection
- worker_version_id in the response
PartialUpdateElement
- worker_version in the response
RetrieveElement
- worker_version in the response
UpdateElement
- worker_version in the response