### 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_
policy_arns = []
    def _create_policy(*args, **kwargs):
        if "PolicyName" not in kwargs:
            kwargs["PolicyName"] = f"policy-{short_uid()}"
        response = iam_client.create_policy(*args, **kwargs)
        policy_arn = response["Policy"]["Arn"]
        policy_arns.append(policy_arn)
        return response
    yield _create_policy
    for policy_arn in policy_arns:
        try:
            iam_client.delete_policy(PolicyArn=policy_arn)
        except Exception:
            LOG.debug("Could not delete policy '%s' during test cleanup", policy_arn)
@pytest.fixture
def create_user(iam_client):