List product field options

curl --request GET \
  --url https://api.shoppex.io/dev/v1/products/{id}/variants/fields/{fieldId}/options \
  --header 'Authorization: Bearer <token>'

{
  "data": [
    {
      "id": "option_1",
      "label": "Europe",
      "value": "eu",
      "sort_order": 0,
      "created_at": 1711953600,
      "updated_at": 1711953900
    }
  ],
  "pagination": {
    "next_cursor": null,
    "has_more": false
  }
}