Option to have Modals not close when a page navigation occurs [Feature Request]

[TravisNorwood]

Is your feature request related to a problem? Please describe.
We use modals for a busy spinner, to show the user processing is being done and keep the user from doing anything with the UI during that time. We'd like to have to option to keep that busy spinner modal open even after navigating to a new page (because some pages take time to do the rendering work and still need a busy spinner showing)

Describe the solution you'd like
Add a boolean on ModalOptions for CloseWhenNavigating (or DontCloseWhenNavigating if you prefer it phrased that way to keep all options false when not set). If this is set, don't close the modal when navigating to a new location.

Describe alternatives you've considered
None

Additional context
None