Cancel a staged import and drop its rows. 409 when not staged. Honours Idempotency-Key. (scope: imports:write)

{  "data": {    "id": "497f6eca-6276-4993-bfeb-53cbbbba6f08",    "entity": "string",    "preset": "string",    "filename": "string",    "source": "string",    "status": "running",    "total_rows": 0,    "imported_count": 0,    "updated_count": 0,    "skipped_count": 0,    "error_count": 0,    "preview": {      "news": 0,      "updates": 0,      "skips": 0,      "errors": 0    },    "reverted_at": "2019-08-24T14:15:22Z",    "created_at": "2019-08-24T14:15:22Z",    "finished_at": "2019-08-24T14:15:22Z"  },  "error": null}