[*]web3:GetMempoolTxHash: fixed error handling

chain/wallet/handlers/MempoolCheckCommand.cpp

@@ -33,6 +33,15 @@ QVariant MempoolCheckCommand::respondToClient(const QVariant &args)
     {
         auto resultValue = cmdList->getJsonResult(requestDoc, "mempool check").result.toArray();
         mempoolAnswer = resultValue[0].toObject();
+
+        if(!mempoolAnswer["errors"].isNull())
+        {
+            QJsonArray errArr = mempoolAnswer["errors"].toArray();
+            if (!errArr.isEmpty())
+            {
+                errorMsg = errArr[0].toObject()["message"].toString();
+            }
+        }
     }
 
     if(args.toStringList().contains(WEB3_KEY))