Unable to test HTTP triggered Azure Functions

### Is there an existing issue for this?

- [x] I have searched the existing issues

### Describe the bug

I built an Aspire project with two HTTP triggered Azure Functions, and other resources. It works well.
Now, when I want to test it using the `DistributedApplicationTestingBuilder` as explained here: https://learn.microsoft.com/en-us/dotnet/aspire/testing/write-your-first-test?pivots=xunit
I get the following error:

```
System.Net.Http.HttpRequestException: No connection could be established because the target computer expressly refused it. (localhost:7072)
---> System.Net.Sockets.SocketException (10061): No connection could be established because the target computer expressly refused it.
at System.Net.Sockets.Socket.AwaitableSocketAsyncEventArgs.ThrowException(SocketError error, CancellationToken cancellationToken)
at System.Net.Sockets.Socket.AwaitableSocketAsyncEventArgs.System.Threading.Tasks.Sources.IValueTaskSource.GetResult(Int16 token)
at System.Net.Sockets.Socket.g__WaitForConnectWithCancellation|285_0(AwaitableSocketAsyncEventArgs saea, ValueTask connectTask, CancellationToken cancellationToken)
at System.Net.Http.HttpConnectionPool.ConnectToTcpHostAsync(String host, Int32 port, HttpRequestMessage initialRequest, Boolean async, CancellationToken cancellationToken)
--- End of inner exception stack trace ---
at System.Net.Http.HttpConnectionPool.ConnectToTcpHostAsync(String host, Int32 port, HttpRequestMessage initialRequest, Boolean async, CancellationToken cancellationToken)
at System.Net.Http.HttpConnectionPool.ConnectAsync(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken)
at System.Net.Http.HttpConnectionPool.CreateHttp11ConnectionAsync(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken)
at System.Net.Http.HttpConnectionPool.AddHttp11ConnectionAsync(QueueItem queueItem)
at System.Threading.Tasks.TaskCompletionSourceWithCancellation`1.WaitWithCancellationAsync(CancellationToken cancellationToken)
at System.Net.Http.HttpConnectionPool.HttpConnectionWaiter`1.WaitForConnectionWithTelemetryAsync(HttpRequestMessage request, HttpConnectionPool pool, Boolean async, CancellationToken requestCancellationToken)
at System.Net.Http.HttpConnectionPool.SendWithVersionDetectionAndRetryAsync(HttpRequestMessage request, Boolean async, Boolean doRequestAuth, CancellationToken cancellationToken)
at System.Net.Http.DiagnosticsHandler.SendAsyncCore(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken)
at System.Net.Http.RedirectHandler.SendAsync(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken)
at Microsoft.Extensions.Http.Logging.LoggingHttpMessageHandler.g__Core|5_0(HttpRequestMessage request, Boolean useAsync, CancellationToken cancellationToken)
at Microsoft.Extensions.Http.Resilience.ResilienceHandler.<>c.<b__3_0>d.MoveNext()
```

### Expected Behavior

The HttpClient for Azure Function resource should work the same as other resources.

### Steps To Reproduce

AppHost.Program.cs
```
var builder = DistributedApplication.CreateBuilder(args);

builder.AddAzureFunctionsProject("functionapp1");

builder.Build().Run();
```
WebTests.cs
```
private static readonly TimeSpan DefaultTimeout = TimeSpan.FromSeconds(300);

[Fact]
public async Task GetWebResourceRootReturnsOkStatusCode()
{
// Arrange
var cancellationToken = new CancellationTokenSource(DefaultTimeout).Token;

var appHost = await DistributedApplicationTestingBuilder.CreateAsync(cancellationToken);
appHost.Services.AddLogging(logging =>
{
logging.SetMinimumLevel(LogLevel.Debug);
// Override the logging filters from the app's configuration
logging.AddFilter(appHost.Environment.ApplicationName, LogLevel.Debug);
logging.AddFilter("Aspire.", LogLevel.Debug);
// To output logs to the xUnit.net ITestOutputHelper, consider adding a package from https://www.nuget.org/packages?q=xunit+logging
});
appHost.Services.ConfigureHttpClientDefaults(clientBuilder =>
{
clientBuilder.AddStandardResilienceHandler();
});

await using var app = await appHost.BuildAsync(cancellationToken).WaitAsync(DefaultTimeout, cancellationToken);
await app.StartAsync(cancellationToken).WaitAsync(DefaultTimeout, cancellationToken);

// Act
var httpClient = app.CreateHttpClient("functionapp1");
await app.ResourceNotifications.WaitForResourceHealthyAsync("functionapp1", cancellationToken).WaitAsync(DefaultTimeout, cancellationToken);
var response = await httpClient.GetAsync("/api/Function1", cancellationToken);

// Assert
Assert.Equal(HttpStatusCode.OK, response.StatusCode);
}
```

### Exceptions (if any)

```
System.Net.Http.HttpRequestException
Aucune connexion n’a pu être établie car l’ordinateur cible l’a expressément refusée. (localhost:7071)
at System.Net.Http.HttpConnectionPool.ConnectToTcpHostAsync(String host, Int32 port, HttpRequestMessage initialRequest, Boolean async, CancellationToken cancellationToken)
at System.Net.Http.HttpConnectionPool.ConnectAsync(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken)
at System.Net.Http.HttpConnectionPool.CreateHttp11ConnectionAsync(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken)
at System.Net.Http.HttpConnectionPool.AddHttp11ConnectionAsync(QueueItem queueItem)
at System.Threading.Tasks.TaskCompletionSourceWithCancellation`1.WaitWithCancellationAsync(CancellationToken cancellationToken)
at System.Net.Http.HttpConnectionPool.SendWithVersionDetectionAndRetryAsync(HttpRequestMessage request, Boolean async, Boolean doRequestAuth, CancellationToken cancellationToken)
at System.Net.Http.RedirectHandler.SendAsync(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken)
at Microsoft.Extensions.Http.Logging.LoggingHttpMessageHandler.g__Core|5_0(HttpRequestMessage request, Boolean useAsync, CancellationToken cancellationToken)
at Microsoft.Extensions.Http.Resilience.ResilienceHandler.<>c.<b__3_0>d.MoveNext()
--- End of stack trace from previous location ---
at Polly.Outcome`1.ThrowIfException()
at Microsoft.Extensions.Http.Resilience.ResilienceHandler.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
at Microsoft.Extensions.Http.Logging.LoggingScopeHttpMessageHandler.g__Core|5_0(HttpRequestMessage request, Boolean useAsync, CancellationToken cancellationToken)
at System.Net.Http.HttpClient.g__Core|83_0(HttpRequestMessage request, HttpCompletionOption completionOption, CancellationTokenSource cts, Boolean disposeCts, CancellationTokenSource pendingRequestsCts, CancellationToken originalCancellationToken)
at AspireApp1.Tests.WebTests.GetWebResourceRootReturnsOkStatusCode() in D:\repos\AspireApp1\AspireApp1.Tests\WebTests.cs:line 43
at AspireApp1.Tests.WebTests.GetWebResourceRootReturnsOkStatusCode() in D:\repos\AspireApp1\AspireApp1.Tests\WebTests.cs:line 46
at Xunit.Sdk.TestInvoker`1.<>c__DisplayClass47_0.<b__1>d.MoveNext() in /_/src/xunit.execution/Sdk/Frameworks/Runners/TestInvoker.cs:line 259
--- End of stack trace from previous location ---
at Xunit.Sdk.ExecutionTimer.AggregateAsync(Func`1 asyncAction) in /_/src/xunit.execution/Sdk/Frameworks/ExecutionTimer.cs:line 48
at Xunit.Sdk.ExceptionAggregator.RunAsync(Func`1 code) in /_/src/xunit.core/Sdk/ExceptionAggregator.cs:line 90

System.Net.Sockets.SocketException
Aucune connexion n’a pu être établie car l’ordinateur cible l’a expressément refusée.
at System.Net.Sockets.Socket.AwaitableSocketAsyncEventArgs.ThrowException(SocketError error, CancellationToken cancellationToken)
at System.Net.Sockets.Socket.AwaitableSocketAsyncEventArgs.System.Threading.Tasks.Sources.IValueTaskSource.GetResult(Int16 token)
at System.Net.Sockets.Socket.g__WaitForConnectWithCancellation|285_0(AwaitableSocketAsyncEventArgs saea, ValueTask connectTask, CancellationToken cancellationToken)
at System.Net.Http.HttpConnectionPool.ConnectToTcpHostAsync(String host, Int32 port, HttpRequestMessage initialRequest, Boolean async, CancellationToken cancellationToken)
```

### .NET Version info

SDK .NET :
Version: 9.0.300
Commit: 15606fe0a8
Workload version: 9.0.300-manifests.af4147de
MSBuild version: 17.14.5+edd3bbf37

Environnement d'exécution :
OS Name: Windows
OS Version: 10.0.22631
OS Platform: Windows
RID: win-x64
Base Path: C:\Program Files\dotnet\sdk\9.0.300\

Charges de travail .NET installées :
Il n'y a aucune charge de travail installée à afficher.
Configuré pour utiliser loose manifests lors de l’installation de nouveaux manifestes.

Host:
Version: 9.0.5
Architecture: x64
Commit: e36e4d1a8f

.NET SDKs installed:
9.0.300 [C:\Program Files\dotnet\sdk]

.NET runtimes installed:
Microsoft.AspNetCore.App 8.0.16 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 9.0.5 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.NETCore.App 8.0.15 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 8.0.16 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 9.0.5 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.WindowsDesktop.App 8.0.15 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 8.0.16 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 9.0.5 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

Other architectures found:
x86 [C:\Program Files (x86)\dotnet]
registered at [HKLM\SOFTWARE\dotnet\Setup\InstalledVersions\x86\InstallLocation]

Environment variables:
Not set

global.json file:
Not found

Learn more:
https://aka.ms/dotnet/info

Download .NET:
https://aka.ms/dotnet/download

### Anything else?

* .NET 8
* Aspire 9.3.0
* Aspire.Hosting.Azure.Functions 9.3.0-preview.1.25265.20
* Visual Studio 17.14.1 Preview 1.0