[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.

src/modules/launcher/PowerLauncher/ResultList.xaml

@@ -32,9 +32,9 @@
     <ListView
         x:Name="SuggestionsList"
         x:FieldModifier="public"
-        BorderBrush="Transparent"
-        Background="Transparent"
         AutomationProperties.Name="{x:Static p:Resources.Results}"
+        Background="Transparent"
+        BorderBrush="Transparent"
         ItemsSource="{Binding Results.Results, Mode=OneWay}"
         ScrollViewer.HorizontalScrollBarVisibility="Disabled"
         ScrollViewer.VerticalScrollBarVisibility="Auto"