TitleBar doesn't respect AppWindow.TitleBar.IconShowOptions

[brunosonnino]

Describe the bug

If you set AppWindow.TitleBar.IconShowOptions to HideIconAndSystemMenu, the icon and the system menu are not hidden

Steps to reproduce the bug

• Create a Blank WinUI3 app
• Upgrade the WindowsAppSdk Nuget package to 1.6 experimental 2
• Change the project file to add

<WindowsSdkPackageVersion>10.0.19041.35-preview</WindowsSdkPackageVersion>

• Add this code in MainWindow.xaml

<StackPanel Orientation="Horizontal">
    <TextBlock Text="Hide AppIcon:" VerticalAlignment="Center"
            Margin="10,0" />
    <ToggleSwitch Toggled="HideIcon_Switched" />
</StackPanel>

And this code to MainWindow.xaml.cs

private void HideIcon_Switched(object sender, RoutedEventArgs e)
{
    if (sender is ToggleSwitch toggleSwitch)
    {
        AppWindow.TitleBar.IconShowOptions = 
            toggleSwitch.IsOn ? IconShowOptions.HideIconAndSystemMenu : IconShowOptions.ShowIconAndSystemMenu;
    }
}

When you tun the code, changing the toggleswitch doesn't change the icon or the system menu

This project shows a sample of the bug: https://github.com/brunosonnino/TitleBarBugs/tree/main/2%20-%20TitleBarHeight

A workaround for this is to set the TitleBar IconSource property to null (but this still shows the system menu)

Expected behavior

The setting should be respected

Screenshots

Icon "Shown"

Icon "Hidden"

NuGet package version

WinUI 3 - Windows App SDK 1.6 Experimental 2: 1.6.240701003-experimental2

Windows version

Windows 11 (22H2): Build 22621

Additional context

No response