XAML style checkers aren't running right now in PR CI. This allowed some XAML style errors to cause build errors in release CI.
This PR contains the following fixes:
- Fix XAML style of files that have slipped.
- Add errors to the scripts that depend on dotnet commands if it fails.
- Add .NET 6 on CI so that applyXamlStyling.ps1 and verifyNugetPackages.ps1 run correctly again.