Make sure the final WiX bundle contains a *signed* MSI

[DHowett]

What is this about:

The Release build pipeline was (1) cleaning the PowerToysSetup solution,
which deleted the recently-signed PowerToys MSI and (2) rebuilding the
PowerToys MSI regardless of cleaning (thanks to WiX.)

This resulted in the final bundle still containing an unsigned MSI
despite all our attempts to sign it.

What is included in the PR:

I've turned off build cleaning and broken the dependency between
PowerToysBootstrapper and PowerToysSetup. This results in msbuild not
running the PowerToysSetup project's build steps at all, and therefore
not overwriting the signed msi with a newly-linked unsigned one.

NOTE: This will impact your ability to F5-run the
bootstrapper from within Visual Studio. Going forward, you'll need to
build the MSI separately before building the bootstrapper.

How does someone test / validate:

See screenshots posted in followup comment.

Quality Checklist

• Linked issue: Installer: internal MSI file is not signed #17410
• Communication: I've discussed this with core contributors in the issue.
• Tests: Added/updated and all pass
• Installer: Added/updated and all pass
• Localization: All end user facing strings can be localized
• Docs: Added/ updated
• Binaries: Any new files are added to WXS / YML
  • No new binaries
  • YML for signing for new binaries
  • WXS for installer for new binaries

[DHowett]

[DHowett]

Ah, the CI pipeline does rely on that dependency. We can fix that, but I want to make sure that this is in the right direction.

[jaimecbernardo]

Why do we need to remove the dependency, though? MSBuild should detect that the file is newer. and that the project doesn't need to be rebuilt.
I think /p:BuildProjectReferences=false would be able to do it as well.
https://docs.microsoft.com/en-us/visualstudio/msbuild/common-msbuild-project-properties?view=vs-2022#list-of-common-properties-and-parameters

[jaimecbernardo]

And thanks for working on the fix :)

[DHowett]

Honestly, the most correct way to fix this would be to have the bundle build process pick up a different input directory for the MSI based on whether CIBuild was set to true. I know that. I am just being lazy.

[jaimecbernardo]

We ended up needing to remove the dependency. Let's go with this.
Thank you for the contribution!