Using objectAtIndex proved to be too brittle when modal contained a MapView

Edge Case:

If the modal contains a MapView as a subview, it adds two extra _UILayoutGuide layers as subviews which throws off the indexing when retrieving the modal and the overlay view from the list of subviews.

Even if having a MapView as a subview of the modal is a rare occurrence, it seems better to retrieve the modal and overlay via their tags rather than rely on them to be at a specific index in the subviews.