Problem with Hosted mqtt server via WebApplicationFactory

I have a problem with integration tests for a hosted mqtt server instance.
Program.cs:

```
builder.WebHost.UseKestrel(w =>
{
w.ListenAnyIP(mqttOptions.Port, l => l.UseMqtt());
w.ListenAnyIP(8100);
});
```
....
```
builder.Services.AddHostedMqttServer(mqttServer =>
{
mqttServer.WithDefaultEndpoint()
.WithDefaultEndpointPort(mqttOptions.Port)
.WithMaxPendingMessagesPerClient(mqttOptions.MaxPendingMessages)
.WithConnectionBacklog(100).WithTlsEndpointReuseAddress();
}).AddMqttConnectionHandler().AddConnections();
```
....
```
app.UseEndpoints(endpoints =>
{
endpoints.MapControllers().RequireCors("AllowAll");
endpoints.MapConnectionHandler(
"/ws",
httpConnectionDispatcherOptions => httpConnectionDispatcherOptions.WebSockets.SubProtocolSelector =
protocolList =>
protocolList.FirstOrDefault() ?? string.Empty);
});
```
Solution works correctly in normal usage but problem exists only in a integration tests when application is set up by `WebApplicationFactory()`.
Server shows `IsStarted` property as `true` and everything gets up correctly until I try to connect via client, then I receive this:

```
MQTTnet.Exceptions.MqttCommunicationException : Error while connecting with host '127.0.0.1:1883'.
---- System.Net.Sockets.SocketException : No connection could be made because the target machine actively refused it.
```

Can someone give me any advice where is the problem?

Nugets:

- MQTTnet 4.1.0.247
- MQTTnet.AspNetCore 4.1.0.247

Env:
- Asp .net core 6
- Windows

Start with the integration test that creates WebApplicationFactory and compare its hosted Kestrel listeners with the Program.cs MQTT configuration. Reproduce the connection attempt to 127.0.0.1:1883 and inspect the factory's effective port and server startup; done means the MQTT client connects successfully in the test environment.

Written by the indexing model from the issue text.