doc(Socket): update auto disconnection sample code (#7706)

* fix(MockDisconnectService): 增加 break 防止异常

* refactor: 移除异常捕获处理代码

Author: ArgoZhang

src/BootstrapBlazor.Server/Services/MockDisconnectService.cs

@@ -48,8 +48,9 @@ private async Task OnDataHandlerAsync(TcpClient client, CancellationToken stoppi
                 await stream.WriteAsync(Encoding.UTF8.GetBytes(DateTime.Now.ToString("yyyyMMddHHmmss")), stoppingToken);
                 await Task.Delay(2000, stoppingToken);
 
-                // 主动关闭连接
+                // 主动关闭连接（关闭后 stream 已释放，必须退出循环）
                 client.Close();
+                break;
             }
             catch (OperationCanceledException) { break; }
             catch (IOException) { break; }