### 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_
"Audio file must be mono PCM WAV format. Transcoding may have failed. "
                )
                raise RuntimeError()
            
            language_code = job["LanguageCode"]
            model_name = LANGUAGE_MODELS[language_code]
            self.download_model(model_name)
            model = Model(model_name=model_name)
            tc = KaldiRecognizer(model, audio.getframerate())
            tc.SetWords(True)
            tc.SetPartialWords(True)
            
            while True:
                data = audio.readframes(4000)
                if len(data) == 0:
                    break
                tc.AcceptWaveform(data)
            tc_result = json.loads(tc.FinalResult())
            
            items = []
            for unigram in tc_result["result"]:
                items.append(
                    {
                        "start_time": unigram["start"],
                        "end_time": unigram["end"],
                        "type": "pronounciation",
                        "alternatives": [
                            {
                                "confidence": unigram["conf"],
                                "content": unigram["word"],