fix link to event page in circular
trying to avoid something like this: https://gracedb-playground.ligo.org/apiweb/events/G0111/files/circular.txt,0
where we're working in gracedb-playground but the circular event link points to gracedb
trying to avoid something like this: https://gracedb-playground.ligo.org/apiweb/events/G0111/files/circular.txt,0
where we're working in gracedb-playground but the circular event link points to gracedb