Enable assistant inbound webhook

{
  "message": "Webhook enabled successfully",
  "data": []
}

{
  "message": "Assistant not found"
}

{
  "message": "The given data was invalid.",
  "errors": {
    "assistant_id": [
      "The assistant id field is required."
    ],
    "webhook_url": [
      "The webhook url field is required."
    ]
  }
}