fix rrt skymap entry for cwb events

The preferred skymap for Burst events (like cwb-bbh and olib) is {pipeline}.png, as opposed to bayestar.png for actual CBC event, which wasn't reflected in the RRT table previously.

Two superevents on gracedb-dev1 had bayestar.png and cwb.png fake skymap files uploaded. Here's a CBC event:

https://gracedb-dev1.ligo.org/superevents/S200323d/view/

here's a cwb-bbh event:

https://gracedb-dev1.ligo.org/superevents/S230711a/view/

If this gets approved while the gracedb-2.28.0 ticket is still in review, I'll drop it in to this release.

Tagging for review:

• @nicolas.arnaud
• @roberto.depietri
• @jenne-driggers

mentioned in issue #347 (closed)

Sorry but I don't feel knowledgeable enough of the GraceDB code to review and approve such change. I understand what the goal is (and agree with that change) but I can't QC the code.

The code change is imo sufficiently minimal that so long as an RRT representative is satisfied with what is being displayed in the table, I can merge it in for release.

merged

mentioned in merge request !223 (merged)

Sound's good to me. Thanks Alex.