message: Add FIXME about not founded get txn
diff: @@ -775,7 +775,7 @@ mod high_cases {
  let get_txn_response = LedgerUtils::submit_request(pool_handle, &get_txn_request).unwrap();
  let get_txn_response: Reply<GetTxnResult> = serde_json::from_str(&get_txn_response).unwrap();
  - assert_eq!(get_txn_response.result.data, "{}".to_string());
  + assert_eq!(get_txn_response.result.data, "{}".to_string()); /* FIXME: unify with other GET_ transactions (data.is_none()) */
  TestUtils::cleanup_storage();
  }
  