Circular template should mention of a single skymap in case contents are the same between first and second preliminary notices
Following https://gracedb.ligo.org/superevents/S200112r/view/ it was raised that in cases where the preferred event does not change between the first and the second preliminary notices, the circular template should mention of only a single skymap filename, or the fact that they are identical as is done in the circular for the event (https://gcn.gsfc.nasa.gov/gcn3/26715.gcn3)