Copy over missing TruthParticle Primary Vertex z position decoration
In MC20 test samples produced with the master_Athena_x86_64-centos7-gcc8-opt/2021-07-08T2101
nightly then it was noted that the PVz
decoration was missing from the Bkg_TruthPileupParticles
container in presampled RDO files and from the TruthPileupParticles
container in the RDO files produced by MC+MC Overlay jobs.
Relates to ATLASSIM-3837
Edited by John Derek Chapman