Since Aspire.Hosting.Testing 9.4 the tests throws TaskCanceledException

### Is there an existing issue for this?

- [x] I have searched the existing issues

### Describe the bug

We are using Aspire.Hosting.Testing.
We recently updated from 9.3 to 9.4.1.

We have started seeing exceptions after the tests have passed so in tear down.

### Expected Behavior

With Aspire 9.4.1 the tests pass and there is no exception thrown.

### Steps To Reproduce

The issue is reproducible with aspire-samples.

1. Clone aspire-samples main from 20th of May (Update to 9.3)
2. Build all projects
3. Open SamplesTests and run a test.

All work fine, and there is no exception.

Do the same but instead with main from 29th of July (Update to 9.4)

### Exceptions (if any)

Exception thrown at AppHosts builder.Build().Run()
AggregateException with a TaskCanceledException as inner exception.

### .NET Version info

.NET SDK:
Version: 9.0.304
Commit: f12f5f689e
Workload version: 9.0.300-manifests.ad61bb1c
MSBuild version: 17.14.16+5d8159c5f

Runtime Environment:
OS Name: Windows
OS Version: 10.0.22631
OS Platform: Windows
RID: win-x64
Base Path: C:\Program Files\dotnet\sdk\9.0.304\

.NET workloads installed:
There are no installed workloads to display.
Configured to use loose manifests when installing new manifests.

Host:
Version: 9.0.8
Architecture: x64
Commit: aae90fa090

.NET SDKs installed:
8.0.206 [C:\Program Files\dotnet\sdk]
8.0.411 [C:\Program Files\dotnet\sdk]
8.0.412 [C:\Program Files\dotnet\sdk]
8.0.413 [C:\Program Files\dotnet\sdk]
9.0.109 [C:\Program Files\dotnet\sdk]
9.0.304 [C:\Program Files\dotnet\sdk]

.NET runtimes installed:
Microsoft.AspNetCore.App 8.0.17 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 8.0.18 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 8.0.19 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 9.0.8 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.NETCore.App 8.0.17 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 8.0.18 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 8.0.19 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 9.0.8 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.WindowsDesktop.App 8.0.17 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 8.0.18 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 8.0.19 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 9.0.8 [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?

Start by comparing aspire-samples from the 9.3 and 9.4 update points, then run a SamplesTests test and inspect the AppHosts builder.Build().Run() teardown path. Reproduce the AggregateException with its TaskCanceledException inner exception and identify why it is raised after the test passes; done means the 9.4.1 scenario completes without the teardown exception.

Written by the indexing model from the issue text.