### Is there an existing issue for this?

- [X] I have searched the existing issues

### Current Behavior

When starting the transcription job in response job object is null:

<img width="1154" alt="Screenshot 2023-04-03 at 09 21 09" src="https://user-images.githubusercontent.com/454412/229447066-1671f811-da49-478d-bf24-252f30b17699.png">


### Expected Behavior

Response from the real AWS stack - job object is not null

<img width="1161" alt="Screenshot 2023-04-03 at 09 30 13" src="https://user-images.githubusercontent.com/454412/229441498-06125248-3b68-4679-8204-0163e8245db6.png">


### How are you starting LocalStack?

Custom (please describe below)

### Steps To Reproduce

Using test containers, reproducing project can be found here:

https://github.com/kkocel/local-stack-transcribe-repro

### Environment

```markdown
- OS: macOS
- LocalStack: latest
```


### Anything else?

_No response_
self,
        context: RequestContext,
        request: StartTranscriptionJobRequest,
    ) -> StartTranscriptionJobResponse:
        job_name = request["TranscriptionJobName"]
        media = request["Media"]
        language_code = request.get("LanguageCode")
        if not language_code:
            raise BadRequestException("Language code is missing")
        if language_code not in LANGUAGE_MODELS:
            raise BadRequestException(f"Language code must be one of {LANGUAGE_MODELS.keys()}")
        store = transcribe_stores[context.account_id][context.region]
        store.transcription_jobs[job_name] = TranscriptionJob(
            TranscriptionJobName=job_name,
            LanguageCode=language_code,
            Media=media,
            CreationTime=datetime.datetime.utcnow(),
            StartTime=datetime.datetime.utcnow(),
            TranscriptionJobStatus=TranscriptionJobStatus.QUEUED,
        )
        start_thread(self._run_transcription_job, (store, job_name))
    def list_transcription_jobs(