Xaml Island Sample fails

[rlaf99]

Describe the bug

A clear and concise description of what the bug is.

Microsoft.Toolkit.Win32.UI.SDK 6.1.2 fails to run the Xaml Island Sample https://github.com/microsoft/Xaml-Islands-Samples/blob/master/NativeXamlIslands.sln in packaged mode.

See https://github.com/microsoft/Xaml-Islands-Samples/issues/46

It appears Microsoft.WinRT.Win32.targets fails to copy some essentials files to AppX folder after build, for example, the following files are missing in AppX folder

.\Microsoft.UI.Xaml.dll
.\Microsoft.UI.Xaml.pri
.\Microsoft.UI.Xaml.winmd
.\SampleLibraryCS.dll
.\SampleLibraryCS.runtimeconfig.json
.\SceneLoaderComponent.dll
.\SceneLoaderComponent.winmd
.\TreeViewHostUserControl.xbf
.\dummy.exe

Steps to Reproduce

Steps to reproduce the behavior:

1. Go to '...'
2. Click on '....'
3. Scroll down to '....'
4. See error

Build https://github.com/microsoft/Xaml-Islands-Samples/blob/master/NativeXamlIslands.sln with Microsoft.Toolkit.Win32.UI.SDK 6.1.2 will give the error.

Build https://github.com/microsoft/Xaml-Islands-Samples/blob/master/NativeXamlIslands.sln Microsoft.Toolkit.Win32.UI.SDK 6.0.0-preview7.1 will give no error.

Expected behavior

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Screenshots

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Environment

NuGet Package(s): 

Package Version(s): 

Project .NET Version:
- [ ] .NET Framework (version: )
- [ ] .NET Core 3
- [ ] .NET Core 3.1 Preview (version: )

Windows 10 Build Number:
- [ ] Fall Creators Update (16299)
- [ ] April 2018 Update (17134)
- [ ] October 2018 Update (17763)
- [ ] May 2019 Update (18362)
- [ ] Insider Build (build number: )
Win 11 22000.556

App min and target version:
- [ ] Fall Creators Update (16299)
- [ ] April 2018 Update (17134)
- [ ] October 2018 Update (17763)
- [ ] May 2019 Update (18362)
- [ ] Insider Build (xxxxx)

Device form factor:
- [x ] Desktop
- [ ] Xbox
- [ ] Surface Hub
- [ ] IoT

Visual Studio 
- [ ] 2017 (version: )
- [ ] 2019 (version: ) 
- [ ] 2019 Preview (version: )
2022

Additional context

Add any other context about the problem here.

Hello zh4ui, thank you for opening an issue with us!

I have automatically added a "needs triage" label to help get things started. Our team will analyze and investigate the issue, and escalate it to the relevant team if possible. Other community members may also look into the issue and provide feedback 🙌

[michael-hawker]

FYI @ocalvo @marb2000