Added PageStyle back to MenuBar to keep it usable until we get proper guidance.

code/TemplateStudioForWinUICs/Templates/_comp/MT/Project.MenuBar/Views/ShellPage.xaml

@@ -7,6 +7,7 @@
     xmlns:animatedvisuals="using:Microsoft.UI.Xaml.Controls.AnimatedVisuals"
     Loaded="OnLoaded"
     Unloaded="OnUnloaded"
+    Style="{StaticResource PageStyle}"
     mc:Ignorable="d">
     <SplitView
         x:Name="splitView"