Howto : .Net8 Authenticated (Azure) SignalR with Blazor Server

### Describe the bug

How do you correctly setup SignalR with authentication on Blazor Server? I created a test project based on the BlazorWebAppOidc:

https://github.com/njannink/BlazorServerAppOidcWithHub/tree/main

Fill in your OIDC + Azure SignalR details in the `BlazorWebAppOidc/Program.cs` file, or you can also turn off Azure SignalR to use the default SignalR hosting model. Everything is working fine when using the InteractiveAuto hosting model, but as soon as you switch to the InteractiveServer way the SignalR connection can no longer be established.

If you then login and try to connect to the chat hub you get the following error:

```
System.IO.InvalidDataException: Invalid negotiation response received.
---> System.Text.Json.JsonReaderException: '<' is an invalid start of a value. LineNumber: 0 | BytePositionInLine: 0.
at System.Text.Json.ThrowHelper.ThrowJsonReaderException(Utf8JsonReader& json, ExceptionResource resource, Byte nextByte, ReadOnlySpan`1 bytes)
at System.Text.Json.Utf8JsonReader.ConsumeValue(Byte marker)
at System.Text.Json.Utf8JsonReader.ReadFirstToken(Byte first)
at System.Text.Json.Utf8JsonReader.ReadSingleSegment()
at System.Text.Json.Utf8JsonReader.Read()
at Microsoft.AspNetCore.Internal.SystemTextJsonExtensions.CheckRead(Utf8JsonReader& reader)
at Microsoft.AspNetCore.Http.Connections.NegotiateProtocol.ParseResponse(ReadOnlySpan`1 content)
--- End of inner exception stack trace ---
at Microsoft.AspNetCore.Http.Connections.NegotiateProtocol.ParseResponse(ReadOnlySpan`1 content)
at Microsoft.AspNetCore.Http.Connections.Client.HttpConnection.NegotiateAsync(Uri url, HttpClient httpClient, ILogger logger, CancellationToken cancellationToken)
at Microsoft.AspNetCore.Http.Connections.Client.HttpConnection.GetNegotiationResponseAsync(Uri uri, CancellationToken cancellationToken)
at Microsoft.AspNetCore.Http.Connections.Client.HttpConnection.SelectAndStartTransport(TransferFormat transferFormat, CancellationToken cancellationToken)
at Microsoft.AspNetCore.Http.Connections.Client.HttpConnection.StartAsyncCore(TransferFormat transferFormat, CancellationToken cancellationToken)
at Microsoft.AspNetCore.Http.Connections.Client.HttpConnection.StartAsync(TransferFormat transferFormat, CancellationToken cancellationToken)
at Microsoft.AspNetCore.Http.Connections.Client.HttpConnectionFactory.ConnectAsync(EndPoint endPoint, CancellationToken cancellationToken)
at Microsoft.AspNetCore.Http.Connections.Client.HttpConnectionFactory.ConnectAsync(EndPoint endPoint, CancellationToken cancellationToken)
at Microsoft.AspNetCore.SignalR.Client.HubConnection.StartAsyncCore(CancellationToken cancellationToken)
at Microsoft.AspNetCore.SignalR.Client.HubConnection.StartAsyncInner(CancellationToken cancellationToken)
at Microsoft.AspNetCore.SignalR.Client.HubConnection.StartAsync(CancellationToken cancellationToken)
at BlazorWebAppOidc.Client.Pages.Chat.OnInitializedAsync() in D:\Projects\blazor\BlazorServerAppOidcWithHub\BlazorWebAppOidc.Client\Pages\Chat.razor:line 43
at Microsoft.AspNetCore.Components.ComponentBase.RunInitAndSetParametersAsync()
at Microsoft.AspNetCore.Components.RenderTree.Renderer.GetErrorHandledTask(Task taskToHandle, ComponentState owningComponentState)
Microsoft.AspNetCore.Components.Server.Circuits.CircuitHost: Error: Unhandled exception in circuit '80pb6dJz85Pl8JrsLdYsB0wQ26jpH6Mi-79i_fPlXZg'.
```

Any help would be greatly appreciated, since we won't be able to switch to Auto/WebAssembly mode anytime soon. I know there is a way to get the access_token from the HttpContext, but as soon as you use Azure SignalR the HttpContextAccessor.HttpContext returns null.

cc: @guardrex https://github.com/dotnet/blazor-samples/issues/204