Fix #6540 (#6556)

* Fix #6540
- just skip the checkRequest call if result of postTransaction is a tx ID

* Fix requestId naming

js/src/api/contract/contract.js

@@ -134,8 +134,10 @@ export default class Contract {
         return this._api.parity
           .postTransaction(encodedOptions)
           .then((requestId) => {
+            if (requestId.length !== 66) {
               statecb(null, { state: 'checkRequest', requestId });
               return this._pollCheckRequest(requestId);
+            } else { return requestId; }
           })
           .then((txhash) => {
             statecb(null, { state: 'getTransactionReceipt', txhash });