curl --request GET \
  --url https://api.merchantops.ai/api/products/export-fields

{
  "property_fields": [
    {
      "key": "<string>",
      "label": "<string>",
      "type": "<string>",
      "hasLabels": true,
      "productTypeCount": 123,
      "propertyType": "<string>",
      "subFields": [
        "<string>"
      ]
    }
  ],
  "system_fields": [
    {
      "key": "<string>",
      "label": "<string>",
      "type": "<string>",
      "hasLabels": true,
      "productTypeCount": 123,
      "propertyType": "<string>",
      "subFields": [
        "<string>"
      ]
    }
  ]
}