Respect the provided subject set id in selection

[camallen]

https://github.com/zooniverse/designator/blob/fb1a535640af4a2ffd3556cffe70f3054f98f315/lib/designator/selection.ex#L111

Only use the supplied by the api, if it is not a known linked workflow subject_set_id then return no data instead of selecting from all known sets.