PowerToys Extension: Use project build because we don't need packagereference

[vanzue]

Summary of the Pull Request

At first version, tried to use the project reference instead of package reference, while it did not work in my local environment, so used package reference instead.

While planned to project reference for many reasons like first day problem explosure in sdk, maintain the strict consistent winmd with the extension host.

Hopefully to solve some of the extension not starting problem.

PR Checklist

• Closes: #xxx

• Communication: I've discussed this with core contributors already. If the work hasn't been agreed, this work might be rejected
• Tests: Added/updated and all pass
• Localization: All end-user-facing strings can be localized
• Dev docs: Added/updated
• New binaries: Added on the required places
  • JSON for signing for new binaries
  • WXS for installer for new binaries and localization folder
  • YML for CI pipeline for new test projects
  • YML for signed pipeline
• Documentation updated: If checked, please file a pull request on our docs repo and link it here: #xxx

Detailed Description of the Pull Request / Additional comments

Validation Steps Performed

Built an installer and validated in my arm64 and x64 machine, works perfectly

[jiripolasek]

LGTM. I have no issue deploying this locally... and that scares me. I'm going to circle back and figure out why I have a problem deploying it with the Extensions SDK from NuGet.org.

As a minor detail, I took the liberty of updating the SLNF for the extension: #46136 - but that just devexp.

[vanzue]

Thanks!!