Remove unused Quantity property in TradeEntry and update EmitTradeTick to use Size as it's always non-negative. (#10)

Author: AdalyatNazirov

QuantConnect.dYdXBrokerage/Models/TradeEntry.cs

@@ -24,5 +24,4 @@ public class TradeEntry
     public OrderDirection Side { get; set; }
     public decimal Price { get; set; }
     public string CreatedAt { get; set; }
-    public decimal Quantity => Side == OrderDirection.Buy ? Size : -Size;
 }

QuantConnect.dYdXBrokerage/dYdXBrokerage.Messaging.cs

@@ -245,11 +245,10 @@ private void HandleTrades(JObject jObj)
         var symbol = _symbolMapper.GetLeanSymbol(trades.Id, SecurityType.CryptoFuture, MarketName);
         foreach (var trade in trades.Contents.Trades)
         {
-            // var tradeValue = trade.Side == OrderSide.Buy ? trade.Value : trade.Value * -1;
             EmitTradeTick(symbol,
                 Time.ParseDate(trade.CreatedAt),
                 trade.Price,
-                trade.Quantity);
+                trade.Size);
         }
     }