Fixed priting of sequences after migration to GaudiConf2
The printing of sequences was broken when "withDetails" options was used. This MR fixes it. (Discovered during dev for !38209 (merged) ) Also there were py2->py3 migrations that were missed and a broken test that are fixed in this MR. Tagging @wlampl @emoyse in case I misunderstood what "withDetails" option was mant for.