aspnet:10.0 - FailFast crash in TypeDescriptor.GetProperties() / ConcurrentDictionary..ctor() after upgrading from 10.0.8 to 10.0.9

### Describe the bug

After upgrading from mcr.microsoft.com/dotnet/aspnet:10.0.8 to 10.0.9, Blazor Server apps crash with an unhandled FailFast during circuit initialization. Rolling back to 10.0.8 resolves the issue. The crash appears to be a regression introduced by the SignalR/Blazor Server fix for CVE-2026-45591.
The crash occurs after a successful SignalR handshake (blazorpack protocol negotiated) and after StartCircuit / UpdateRootComponents hub invocations complete. It happens during component rendering when TypeDescriptor.GetProperties() is called.

### Which .NET image(s) are you using?

mcr.microsoft.com/dotnet/aspnet:10.0@sha256:ca4d5abeddde5736b1ed2459cec1168af6a9abc710941816415dac00e16d5831

### Steps to reproduce

1. Run a Blazor Server app using mcr.microsoft.com/dotnet/aspnet:10.0.9
2. Behind a reverse proxy (Traefik) with WebSocket support
3. Navigate to a page that loads data and renders components on OnInitializedAsync
4. Process crashes with FailFast — no managed exception is catchable

### Other information

Process terminates immediately with:
```
Process terminated. UnhandledException
at System.Environment.FailFast(...)
at System.Runtime.EH.FallbackFailFast(System.Runtime.RhFailFastReason, System.Object)
at System.Runtime.EH.UnhandledExceptionFailFastViaClasslib(...)
at System.Runtime.EH.DispatchEx(...)
at System.Collections.Concurrent.ConcurrentDictionary`2..ctor()
at System.ComponentModel.TypeDescriptor+DefaultTypeDescriptor.GetProperties()
```
With a native crash dump (when enabled) showing:
```
[createdump] Crashing thread 000f signal 11 (000b)
[createdump] Writing minidump with heap to file /tmp/coredump.1
```

### Output of `docker version`

```console

```

### Output of `docker info`

```console

```

Reproduce the crash with the aspnet:10.0.9 image, a Blazor Server app, and the listed SignalR circuit flow; compare behavior with 10.0.8. Start at TypeDescriptor.GetProperties() and ConcurrentDictionary..ctor() after StartCircuit and UpdateRootComponents, then inspect the native dump if available. Done means component rendering completes without FailFast on 10.0.9.

Written by the indexing model from the issue text.