Segments showing as "Used" for Archived experiments #3036
Description
Currently we don't allow deleting Segments if they're "Used". But there are cases when we have Archived an experiment but no longer need the segment associated with it. When an experiment is Archived, it is a terminal state so the Used state of the segment should be released. One way to deal with this is for the Archived experiment to preserve only the string of the segment name in its include/exclude lists, so it could potentially be used for reference but allow the segment to not show as Used.
