Fix Mistral transcription requests

[NoelDeMartin]

I recently upgraded my laravel/framework version, and I started getting errors from Mistral's transcription API. In particular, I got the following:

{
  "object": "error",
  "message": {
    "detail": [
      {
        "type": "assertion_error",
        "loc": [],
        "msg": "Assertion failed, When diarize is set to True and streaming is disabled, the timestamp granularity must be set to ['segment'], got []",
        "input": {
          "model": "voxtral-mini-latest",
          "audio": "--audio-bytes--",
          "language": null,
          "temperature": null,
          "max_tokens": null,
          "stream": false,
          "return_language": false,
          "streaming": "disabled",
          "timestamp_granularities": [],
          "diarize": true,
          "context_bias": [],
          "target_streaming_delay_ms": null,
          "metadata": null
        },
        "ctx": {
          "error": {}
        }
      }
    ]
  },
  "type": "invalid_request_error",
  "param": null,
  "code": null,
  "raw_status_code": 422
}

Looking at the code, I was confused because the timestamp_granularities seems to be set to "segments" in the code... but after some digging, I could trace back the regression to a recent PR in laravel/framework: laravel/framework#59984

This was released in v13.9.0, and I'm not sure how many things are broken because of that. At the very least, this PR fixes Mistral's transcriptions.

I have reported this issue to laravel/framework in case you want to take a look at a more general fix: laravel/framework#60319