[CI Failure] Flaky: JsonRpcAuthenticationTests.FailedAuthentication_ClosesConnection_AndPreventsFurtherCalls times out connecting to named pipe RPC server

## Build Information

Build: https://github.com/microsoft/aspire/actions/runs/29787895542
Build error leg or test failing: Tests / Hosting.RemoteHost / Hosting.RemoteHost (windows-latest) / `Aspire.Hosting.RemoteHost.Tests.JsonRpcAuthenticationTests.FailedAuthentication_ClosesConnection_AndPreventsFurtherCalls`
Pull request: #18835

## Error Message

```
System.TimeoutException : Timed out connecting to test RPC server 'aspire-remotehost-test-...'.
---- System.OperationCanceledException : The operation was canceled.
at Aspire.Hosting.RemoteHost.Tests.JsonRpcAuthenticationTests.RemoteHostTestServer.ConnectToServerAsync(...) in /_/tests/Aspire.Hosting.RemoteHost.Tests/JsonRpcAuthenticationTests.cs:line 220
at System.IO.Pipes.NamedPipeClientStream.ConnectInternal(Int32 timeout, CancellationToken cancellationToken, Int32 startTime)
```

## Description

Flaky: JsonRpcAuthenticationTests.FailedAuthentication_ClosesConnection_AndPreventsFurtherCalls times out connecting to named pipe RPC server

**Type**: flaky-test

## Occurrences

| Date | Build | Job | PR |
|------|-------|-----|----|
| 2026-07-21 | [29787895542](https://github.com/microsoft/aspire/actions/runs/29787895542) | Tests / Hosting.RemoteHost / Hosting.RemoteHost (windows-latest) | #18835 |

Start with tests/Aspire.Hosting.RemoteHost.Tests/JsonRpcAuthenticationTests.cs, especially ConnectToServerAsync at line 220 and FailedAuthentication_ClosesConnection_AndPreventsFurtherCalls. Run the named test on the windows-latest configuration and inspect the RPC server startup and connection timing. Done means the test no longer intermittently times out while retaining its authentication and connection-closure assertions.

Written by the indexing model from the issue text.