Empty Page for Lightbox Modal redirect (such as on Delete)

When performing a delete action (and possibly others) from within a lightbox modal, PE needs to redirect to an empty page for displaying messaging to a user inside the lightbox. The user can then dismiss the modal, just as when editing or viewing in the modal, prompting a reload of the underlying page - such as an index view.

At the moment, delete of an item will most often redirect to an index view which causes that index view to appear in the modal window, which is undesirable.

This is needed for many purposes, but at the time of ticket creation particularly important for deletion of a single Group Member (because group member edits are managed in the modal).