Fixing rare errors for large-R jets in derivation productions
This MR fixes a couple of issues that were observed in recent derivation productions in ATLASDPD-1877
(1) A WARNING was printed out many times if no PV is present resulting in huge log files. This has been downgraded to VERBOSE as for the other tools in JetMomentTools.This was also reported in ATLJETMET-1577
(2) An error appeared in SoftDropObservables when jets were passed to the tool with only one constituent. At least two constituents are not required or otherwise the variables are not calculated.
(3) Errors started appearing in JetTruthLabellingTool in the rare case that a jet after trimming has zero constituents. In the jet substructure calculations, we check for the number of constituents but it was missed in this tool. This should fix the issues observed in ATLJETMET-1570
Tagging a few people who reported issues: @eting @dcamarer @mswiatlo @schaarsc