[BUG]: SubwayNav Control display mode does not affect child items

[niklaswimmer]

Describe the bug
When the display mode of a SubwayNav Control is set to Disabled, it is no longer possible to select the top level items - which is expected. However, it is still possible to select the child items and therefore change the state of the control.

To Reproduce
Steps to reproduce the behavior:

1. Add a SubwayNav Control to your Application
2. Set its items property to something like Table({ItemKey:"toplevel1",ItemLabel:"Top Level 1",ItemState:"CurrentWithSubsteps"},{ItemKey:"child1",ItemLabel:"Child 1",ItemState:"Current",ParentItemKey:"toplevel1"},{ItemKey:"child2",ItemLabel:"Child 2",ParentItemKey:"toplevel1"},{ItemKey:"toplevel2",ItemLabel:"Top Level 2"})
3. Set the display mode to DisplayMode.Disabled
4. observe how it is no longer possible to select the top level items but still possible to switch between the two child items

Expected behavior
If the SubwayNav Control is in disabled mode (or view, I do not quite understand why it stays interactive in view mode but that is another problem I guess) no part of the control should be selectable.

AB#2948

[denise-msft]

Thank you for reporting this issue. We will prioritize fixing this as resources permit and will provide an update when possible.