Update tests/Responses/ResponsesToolTests.cs

Co-authored-by: Copilot <[email protected]>

Author: joseharriaga

tests/Responses/ResponsesToolTests.cs

@@ -12,7 +12,6 @@
 using System.IO;
 using System.Linq;
 using System.Text;
-using System.Threading;
 using System.Threading.Tasks;
 using static OpenAI.Tests.TestHelpers;