Remove unused import

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: codez0mb1e

tests/BinanceBot.Market.Tests/MarketDepthManagerTests.cs

@@ -1,7 +1,6 @@
 using System.Threading;
 using System.Threading.Tasks;
 using Binance.Net.Interfaces.Clients;
-using BinanceBot.Market.Core;
 using BinanceBot.Market.Domain;
 using Moq;
 using NLog;