FST pop-up relabelling punches through way too many levels of abstraction

[eddieantonio]

Follow up on #920. It works, but the DisplayMode preference needs to be carried through from the view, through the search run, down into presentation results so that it can be finally used to relabel the relevant_tags.

The DisplayMode preference must be derived from the request. What is the point of serialization presentation result?

Is there a cleaner way to do this?