curl --request GET \
  --url https://core.ravenna.ai/api/request-type-custom-fields \
  --header 'x-ravenna-api-token: <api-key>'

{
  "items": [
    {
      "id": "<string>",
      "order": 123,
      "private": true,
      "requestTypeId": "<string>",
      "customField": {
        "id": "<string>",
        "workspaceId": "<string>",
        "key": "<string>",
        "label": "<string>",
        "description": "<string>",
        "required": true,
        "system": true,
        "config": null,
        "type": "TEXT",
        "options": [
          {
            "id": "<string>",
            "value": "<string>",
            "order": 123,
            "description": "<string>",
            "color": "<string>",
            "icon": "<string>",
            "customFieldId": "<string>",
            "createdAt": "<string>",
            "updatedAt": "<string>"
          }
        ],
        "createdAt": "<string>",
        "updatedAt": "<string>",
        "_count": {
          "requestTypeCustomField": 123
        }
      },
      "customFieldId": "<string>",
      "ticketField": "TITLE",
      "required": true,
      "createdAt": "<string>",
      "updatedAt": "<string>",
      "parentId": "<string>"
    }
  ],
  "nextCursor": "<string>",
  "totalCount": 123
}