Remove unnecessary _connectCts field from McpClientImpl

Co-authored-by: stephentoub <2642209+stephentoub@users.noreply.github.com>

Author: Copilot

src/ModelContextProtocol.Core/Client/McpClientImpl.cs

@@ -22,8 +22,6 @@ internal sealed partial class McpClientImpl : McpClient
     private readonly SemaphoreSlim _disposeLock = new(1, 1);
     private readonly McpTaskCancellationTokenProvider? _taskCancellationTokenProvider;
 
-    private CancellationTokenSource? _connectCts;
-
     private ServerCapabilities? _serverCapabilities;
     private Implementation? _serverInfo;
     private string? _serverInstructions;
@@ -526,9 +524,6 @@ private void RegisterTaskHandlers(RequestHandlers requestHandlers, IMcpTaskStore
     /// </summary>
     public async Task ConnectAsync(CancellationToken cancellationToken = default)
     {
-        _connectCts = CancellationTokenSource.CreateLinkedTokenSource(cancellationToken);
-        cancellationToken = _connectCts.Token;
-
         try
         {
             // We don't want the ConnectAsync token to cancel the message processing loop after we've successfully connected.