remove unneeded using

Author: jaredpar

tests/ModelContextProtocol.Tests/Transport/SseClientTransportTests.cs

@@ -5,7 +5,6 @@
 using ModelContextProtocol.Tests.Utils;
 using System.Net;
 using System.Reflection;
-using System.Reflection.Metadata;
 
 namespace ModelContextProtocol.Tests.Transport;