### 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_
import datetime
import json
import logging
import os
import threading
import wave
from pathlib import Path
from typing import Tuple
from zipfile import ZipFile
from localstack import config
from localstack.aws.api import RequestContext, handler
from localstack.aws.api.transcribe import (
    BadRequestException,
    GetTranscriptionJobResponse,
    ListTranscriptionJobsResponse,
    MaxResults,
    MediaFormat,
    NextToken,
    NotFoundException,
    StartTranscriptionJobRequest,
    StartTranscriptionJobResponse,
    TranscribeApi,
    Transcript,
    TranscriptionJob,
    TranscriptionJobName,
    TranscriptionJobStatus,
    TranscriptionJobSummary,