Update NavigationView to meet MAS 4.1.2

Describe the bug When testing our app accessibility, we had a bug assigned to us where the control type reported by the accessibility tool is not the expected one for NavigationViewItem and was breaking WCAG rule 4.1.2. The NavigationViewItem are reporting a ListItem control type whereas they should report TabItem.

According to the AutomationControlType documentation we have:

• ListItem: A list item control, which is a child item of a list control.
• TabItem: A tab item control, which represents a page of a tab control.

TabItem is a better fit for the navigation items.

Steps to reproduce the bug

1. Create an application with a navigation view with one or more navigation item.
2. Run the application
3. Run accessibility insights tool or the Windows narrator

Expected behavior The NavigationViewItem should report AutomationControlType.TabItem as their control type

Screenshots

Version Info NuGet package version: Microsoft.UI.Xaml 2.2.190917002

[jevansaks]

So the change would be: change the role dynamically; ListItem in left nav and TabItem in top nav?

[mdtauk]

If they perform a navigation, they behave like tabs.

If they display a flyout, they behave more like menu items.