Only return valid stopwatches (#19863)
Looking through the logs of try.gitea.io I am seeing a number of reports
of being unable to APIformat stopwatches because the issueID is 0. These
are invalid StopWatches and they represent a db inconsistency.
This PR simply stops sending them to the eventsource.
Signed-off-by: Andrew Thornton <art27@cantab.net>
Co-authored-by: techknowlogick <techknowlogick@gitea.io>