[Shell] [WinUI] TitleView always shows ShellContent title, even if it's set.

[drasticactions]

Description

When using Shell, you can set a TitleView to have dynamic content appear in the top bar of your app, for example.

    <Shell.TitleView>
        <Label Text="Test"/>
    </Shell.TitleView>

Normally, if you set this content, it will clear the existing header and use this one. However, when using WinUI, it still shows the existing ShellContent title, showing both.

I don't think this is the intended functionality, as iOS, Mac Catalyst, and Android all clear the title content correctly. I think this is a bug.

Steps to Reproduce

1. Create a new MAUI App.
2. In the default ContentPage, add

    <Shell.TitleView>
        <Label Text="Test"/>
    </Shell.TitleView>

Version with bug

Release Candidate 1 (current)

Last version that worked well

Unknown/Other

Affected platforms

Windows

Affected platform versions

Windows SDK Whatever Current Version It Is.

Did you find any workaround?

No response

Relevant log output

No response