Get product variant field

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

{
  "data": {
    "id": "field_1",
    "name": "Region",
    "type": "select",
    "required": true,
    "placeholder": null,
    "default_value": null,
    "sort_order": 0,
    "options": [],
    "created_at": 1711953600,
    "updated_at": 1711953900
  }
}