Retrieve available voices

{
  "supported_voices": [
    {
      "voice_id": "<string>",
      "service": "eleven",
      "name": "<string>",
      "description": "<string>",
      "labels": {},
      "preview_url": "<string>",
      "premium": false,
      "user_id": "<string>",
      "created_at": "2023-11-07T05:31:56Z",
      "updated_at": "2023-11-07T05:31:56Z"
    }
  ]
}