curl --request DELETE \
  --url https://{cluster}.voucherify.io/v1/validation-rules/{validationRuleId} \
  --header 'X-App-Id: <api-key>' \
  --header 'X-App-Token: <api-key>'

{
  "code": 404,
  "key": "not_found",
  "message": "Resource not found",
  "details": "Cannot find validation_rules with id val_TGN3rqZ8vEm",
  "request_id": "v-0ae3b3436346b778be",
  "resource_id": "val_TGN3rqZ8vEm",
  "resource_type": "validation_rules"
}