Remove restriction to internal users on creating TranscriptionEntity with a worker version

https://gitlab.com/arkindex/backend/-/merge_requests/1700#note_954519873

CreateTranscriptionEntity forbids creating a TranscriptionEntity with a worker version for non-internal users. We decided to remove this restriction for worker runs, as most endpoints do not apply it and it is not necessary. The restriction can also be lifted for worker versions without worker runs.