link-proxy-hook: remove unnecessary %gu scry
This is redundant as the metadata store will always boot before the
link-proxy-hook.
`t.t.path
~
?~ target |
- ~? !.^(? %gu (scot %p our.bowl) %metadata-store (scot %da now.bowl) ~)
- %woah-md-s-not-booted ::TODO fallback if needed
%+ lien (groups-from-resource:md %link u.target)
|= =group-path
^- ?
