DropDownButton support for the ContextMenu Placement option in flyout

[paulober]

Is your feature request related to a problem? Please describe

If you create a DropDownButton with a Flyout that includes ContextMenu Placment=Top it doesn't respect that setting:

<ui:NavigationView.PaneFooter>
    <ui:DropDownButton Content="Ansicht" Margin="0,0,0,10" Background="Transparent" HorizontalAlignment="Stretch">
        <ui:DropDownButton.Flyout>
            <ContextMenu Placement="Top">
                <ui:MenuItem Header="Stammdaten"/>
                <ui:MenuItem Header="Einstellungen"/>
            </ContextMenu>
        </ui:DropDownButton.Flyout>
    </ui:DropDownButton>
</ui:NavigationView.PaneFooter>

Describe the solution you'd like

That the Placment option of the ContextMenu defines where the DropDownButton opens the Flyout like the MenuFlyout in WinUI.

Describe alternatives you've considered

No response

Additional context

No response