Depends on https://github.com/nix-community/nix-eval-jobs/pull/349 & #1421.
Almost equivalent to #1425, but with a small change: when having e.g. an
aggregate job with a glob that matches nothing, the jobset evaluation is
failed now. This was the intended behavior before (hydra-eval-jobset
fails hard if an aggregate is broken), the code-path was never reached
however since the aggregate was never marked as broken in this case
before.
