Quarantine HubConnectionTests.RefreshChangingUserIdentifierClosesConnection

## Failing Test(s)

`Microsoft.AspNetCore.SignalR.Client.FunctionalTests.HubConnectionTests.RefreshChangingUserIdentifierClosesConnection`

## Failure Frequency

Failed 11 times over the past 30 days.

## Error Message

```text
System.Net.Http.HttpRequestException: Response status code does not indicate success: 403 (Forbidden).
at System.Net.Http.HttpResponseMessage.EnsureSuccessStatusCode()
at Microsoft.AspNetCore.Http.Connections.Client.Internal.LongPollingTransport.SendDeleteRequest(Uri url) in /_/src/SignalR/clients/csharp/Http.Connections.Client/src/Internal/LongPollingTransport.cs:line 244
```

## Stacktrace

Stack trace

```text
Microsoft.AspNetCore.Http.Connections.Client.Internal.LongPollingTransport - ErrorSendingDeleteRequest - Error sending DELETE request to '(127.0.0.1/redacted)
===================
System.Net.Http.HttpRequestException: Response status code does not indicate success: 403 (Forbidden).
at System.Net.Http.HttpResponseMessage.EnsureSuccessStatusCode()
at Microsoft.AspNetCore.Http.Connections.Client.Internal.LongPollingTransport.SendDeleteRequest(Uri url) in /_/src/SignalR/clients/csharp/Http.Connections.Client/src/Internal/LongPollingTransport.cs:line 244
===================
at Microsoft.AspNetCore.SignalR.Tests.VerifyNoErrorsScope.Dispose()
at Microsoft.AspNetCore.SignalR.Tests.InProcessTestServer`1.DisposeAsync() in /_/src/Shared/SignalR/InProcessTestServer.cs:line 168
at Microsoft.AspNetCore.SignalR.Client.FunctionalTests.HubConnectionTests.RefreshChangingUserIdentifierClosesConnection(HttpTransportType transportType) in /_/src/SignalR/clients/csharp/Client/test/FunctionalTests/HubConnectionTests.AuthenticationRefresh.cs:line 389
```

## Logs

Console log excerpt

```text
[xUnit.net 00:04:12.74] | [0.162s] TestLifetime Information: Finished test RefreshChangingUserIdentifierClosesConnection-ServerSentEvents in 0.1617042s
[xUnit.net 00:04:12.77] Microsoft.AspNetCore.SignalR.Client.FunctionalTests.HubConnectionTests.RefreshChangingUserIdentifierClosesConnection(transportType: LongPolling) [FAIL]
[xUnit.net 00:04:12.78] 1 error(s) logged.
[xUnit.net 00:04:12.78] Microsoft.AspNetCore.Http.Connections.Client.Internal.LongPollingTransport - ErrorSendingDeleteRequest - Error sending DELETE request to '(127.0.0.1/redacted)
[xUnit.net 00:04:12.78] System.Net.Http.HttpRequestException: Response status code does not indicate success: 403 (Forbidden).
[xUnit.net 00:04:12.78] at System.Net.Http.HttpResponseMessage.EnsureSuccessStatusCode()
[xUnit.net 00:04:12.78] at Microsoft.AspNetCore.Http.Connections.Client.Internal.LongPollingTransport.SendDeleteRequest(Uri url)
```

## Build

https://dev.azure.com/dnceng-public/public/_build/results?buildId=1533724&view=results

> Generated by [Daily Test Quarantine Management](https://github.com/dotnet/aspnetcore/actions/runs/30695956287) · sonnet46 · 667 AIC · ⌖ 9.69 AIC · ⊞ 3.3K · [◷](https://github.com/search?q=repo%3Adotnet%2Faspnetcore+is%3Aissue+%22gh-aw-workflow-call-id%3A+dotnet%2Faspnetcore%2Ftest-quarantine%22&type=issues)

Start with RefreshChangingUserIdentifierClosesConnection in src/SignalR/clients/csharp/Client/test/FunctionalTests/HubConnectionTests.AuthenticationRefresh.cs, then inspect LongPollingTransport.SendDeleteRequest at the reported line. Run the test with the LongPolling transport and compare the 403 response with the connection refresh flow. Done means the test no longer fails intermittently or logs an unexpected DELETE error.

Written by the indexing model from the issue text.