CI: don't test for summary page for gracedb test

The bilby_pipe_gracedb default options no longer produce summary pages and so the CI job is failing.

I've also temporarily removed this from the schedules only, @gregory.ashton do you remember why this was only run on the schedule (I don't see any discussion around #144 (closed))? It doesn't take very long to run, I guess there's a potential concern about overloading gwosc? We could make it master only to avoid that?

Since this is not part of the online workflow in O4, I've just updated the test to check the correct final state (the final combined result file).