Given the note is about how to interpret ancestor clusters, use the
finder which actually knows if there are any ancestor clusters to find
out if the note should be shown, rather than passing the same info via a
view to a helper

Added note about Kaminari.paginate_array

Link to followup issue too

This is in addtion to the can checks we have in the controller, as a
finder can be used elsewhere in the future.

Show both the cluster(s) of the clusterable, and the cluster(s) of
ancestor groups.