List webhook endpoints

curl --request GET \
  --url https://api.us.poly.ai/v1/webhook-endpoints \
  --header 'x-api-key: <api-key>'

{
  "data": [
    {
      "id": "whe_9ZtRcXw3nByK5pVqMaEfJs",
      "name": "<string>",
      "url": "<string>",
      "enabled": true,
      "event_types": [
        "alerts.triggered"
      ],
      "timeout_ms": 5000,
      "created_at": "2023-11-07T05:31:56Z",
      "updated_at": "2023-11-07T05:31:56Z",
      "headers": {}
    }
  ]
}