Solution: Preserve LightSwitchService unit test project GUID in solution #51402

Summary of the Pull Request

This PR updates SLNX to include correct project id used by LightSwitchService.UnitTests.vcxproj.

The project entry in PowerToys.slnx was missing an explicit id, so the solution parser generated a GUID different from the project's existing ProjectGuid. Visual Studio then rewrote the vcxproj file, producing unwanted Git changes whenever the solution was loaded.

https://github.com/microsoft/PowerToys/blob/ef43bf8ff5f3678f860a05227ea668825b967bf6/src/modules/LightSwitch/Tests/LightSwitchService.UnitTests/LightSwitchService.UnitTests.vcxproj#L7

• Sets the solution entry's Id to the existing ProjectGuid to keep both identities consistent and prevent the automatic rewrite.

PR Checklist

• [ ] Closes: #xxx
  <!-- - [ ] Closes: #yyy (add separate lines for additional resolved issues) -->


• [ ] 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