### 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_
def _wait_for_cluster(domain_name: str):
        def finished_processing():
            status = opensearch_client.describe_domain(DomainName=domain_name)["DomainStatus"]
            return status["Processing"] is False
        assert poll_condition(
            finished_processing, timeout=5 * 60
        ), f"could not start domain: {domain_name}"
    return _wait_for_cluster
@pytest.fixture
def opensearch_create_domain(opensearch_client, opensearch_wait_for_cluster):
    domains = []
    def factory(**kwargs) -> str:
        if "DomainName" not in kwargs:
            kwargs["DomainName"] = f"test-domain-{short_uid()}"
        opensearch_client.create_domain(**kwargs)
        opensearch_wait_for_cluster(domain_name=kwargs["DomainName"])
        domains.append(kwargs["DomainName"])
        return kwargs["DomainName"]
    yield factory
    
    for domain in domains:
        try:
            opensearch_client.delete_domain(DomainName=domain)
        except Exception as e:
            LOG.debug("error cleaning up domain %s: %s", domain, e)
@pytest.fixture
def opensearch_domain(opensearch_create_domain) -> str: