[ci]Fix running xaml styles in CI (#35426)

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.

.pipelines/verifyNugetPackages.ps1

@@ -8,6 +8,12 @@ Write-Host "Verifying Nuget packages for $solution"
 
 dotnet tool restore
 dotnet consolidate -s $solution
+if ($lastExitCode -ne 0)
+{
+    $result = $lastExitCode
+    Write-Error "Error running dotnet consolidate, with the exit code $lastExitCode. Please verify logs and running environment."
+    exit $result
+}
 
 if (-not $?)
 {