List customers

curl --request GET \
  --url https://gateway-api.guardhousehq.com/api/external/customers \
  --header 'Authorization: Bearer <token>'

{
  "status": {
    "code": 123,
    "errorMessage": "<string>"
  },
  "data": [
    {
      "id": 123,
      "name": "<string>",
      "customerReferenceNumber": "<string>",
      "referenceId": "<string>",
      "customerAPIReferenceField": "<string>",
      "address": "<string>",
      "city": "<string>",
      "state": "<string>",
      "zip": "<string>",
      "country": "<string>"
    }
  ],
  "count": 123,
  "message": "<string>",
  "errors": [
    {
      "code": 100,
      "message": "<string>"
    }
  ],
  "nextPageParameter": "<string>",
  "prevPageParameter": "<string>"
}