[CI Failure] Flaky: ContainerTunnelTests.ProxylessEndpointWorksWithContainerTunnel times out with socket cancellation

## Build Information

Build: https://github.com/microsoft/aspire/actions/runs/32053958727
Build error leg or test failing: Tests / Hosting-2 / Hosting-2 (8-core-ubuntu-latest) / `Aspire.Hosting.Tests.ContainerTunnelTests.ProxylessEndpointWorksWithContainerTunnel`
Pull request: #19400

## Error Message

```
Polly.Timeout.TimeoutRejectedException : The operation didn't complete within the allowed timeout of '00:00:30'. ---- System.Threading.Tasks.TaskCanceledException : The operation was canceled. ---- System.IO.IOException : Unable to read data from the transport connection: Operation canceled. ---- System.Net.Sockets.SocketException : Operation canceled
```

## Description

Flaky: ContainerTunnelTests.ProxylessEndpointWorksWithContainerTunnel times out with socket cancellation

**Type**: flaky-test

## Occurrences

| Date | Build | Job | PR |
|------|-------|-----|----|
| 2026-08-17 | [32053958727](https://github.com/microsoft/aspire/actions/runs/32053958727) | Tests / Hosting-2 / Hosting-2 (8-core-ubuntu-latest) | #19400 |

Start with ContainerTunnelTests.ProxylessEndpointWorksWithContainerTunnel and the linked build's Hosting-2 test leg. Investigate the 30-second timeout, TaskCanceledException, and socket cancellation, then verify the test no longer flakes or times out in CI.

Written by the indexing model from the issue text.