Revert WinUI sample PackagedApp reference until packaged-app launch is supported

[Evangelink]

Summary

This surgically reverts the three sample changes introduced by #9908 ("Wire WinUI MTP sample to Microsoft.Testing.Extensions.PackagedApp"), restoring the MSTestRunnerWinUI sample to its previous, working in-process state.

Why

The WinUI sample (samples/public/mstest-runner/MSTestRunnerWinUI) is a packaged (MSIX) app (EnableMsixTooling=true, Package.appxmanifest, ProjectCapability Include="Msix"). Referencing Microsoft.Testing.Extensions.PackagedApp auto-registers its ITestHostLauncher, which forces the platform's controller / deploy-and-launch path (registering any launcher sets requireProcessRestart=true).

However, the current PackagedAppTestHostLauncher only performs a CopyDirectory + Process.Start of the loose layout copy — it cannot launch a packaged/MSIX app. Proper PackageManager registration + AUMID activation is still a pending follow-up (#2784). As a result, #9908 made the sample build successfully but fail at launch, so it no longer demonstrates the intended runtime flow.

This reverts the reference until packaged-app (AUMID) activation lands, at which point the sample can be re-wired.

Changes

1. MSTestRunnerWinUI.csproj — removed the Microsoft.Testing.Extensions.PackagedApp PackageReference and its explanatory comment. Other references (MSTest, WindowsAppSDK, etc.) are untouched.
2. samples/public/Directory.Build.props — removed the MicrosoftTestingExtensionsPackagedAppVersion property and its comment. TestingPlatformVersion (2.3.2) is unchanged.
3. UnitTestApp.xaml.cs — removed the comment block above builder.AddSelfRegisteredExtensions(cliArgs);, restoring the original adjacency of the two builder calls.

Verification

• Built with the repo SDK: dotnet build samples\public\mstest-runner\MSTestRunnerWinUI\MSTestRunnerWinUI.slnx -c Release -p:Platform=x64 -p:TreatWarningsAsErrors=true → 0 Warning(s), 0 Error(s).
• Confirmed the generated obj/.../SelfRegisteredExtensions.cs no longer contains Microsoft.Testing.Extensions.PackagedApp.

References

• Reverts sample changes from Wire WinUI MTP sample to Microsoft.Testing.Extensions.PackagedApp #9908
• Blocked-on follow-up: Add support for testing unpackaged WinUI applications #2784 (packaged-app / AUMID activation)

[Copilot]

Pull request overview

Restores the WinUI sample’s working in-process execution until packaged/MSIX activation is supported.

Changes:

• Removes the PackagedApp package reference and version property.
• Removes obsolete launcher registration comments.

Show a summary per file

File	Description
UnitTestApp.xaml.cs	Removes obsolete PackagedApp registration commentary.
MSTestRunnerWinUI.csproj	Removes the PackagedApp package reference.
Directory.Build.props	Removes the unused PackagedApp version property.

Review details

• Files reviewed: 3/3 changed files
• Comments generated: 0
• Review effort level: Medium

[github-actions]

Note

🤖 Automated review by GitHub Copilot. Generated by the Expert Code Review workflow. To request a follow-up action, reply by tagging @copilot directly.

Expert Review Summary — PR #9913

Verdict: ✅ LGTM — clean revert of a broken sample reference.

This PR reverts the Microsoft.Testing.Extensions.PackagedApp additions from PR #9908 that made the WinUI sample runtime-broken (the launcher forced requireProcessRestart=true but can't actually launch an MSIX-packaged app yet).

Dimension Assessment

Dimension	Rating	Notes
Correctness	✅	Removes the root cause of the runtime breakage.
Completeness	✅	All three touchpoints (version property, PackageReference, code comment) reverted consistently.
Backward Compat	N/A	Sample code only.
Error Handling	N/A	No logic changes.
Security	N/A
Performance	N/A
Thread Safety	N/A
Public API	N/A	Sample project.
Localization	N/A
Documentation	✅	Comment removal appropriate — described behavior no longer applies.
Testing	N/A	WinUI sample not in CI.
Build Integration	✅	No orphaned properties.
Code Style	✅	Consistent with repo conventions.
Traceability	✅	References PR #9908 and issue #2784.

No actionable findings. Ship it. 🚀