GeneratorFilters: fix logic of the (xAOD)XtoVVDecayFilterExtended.cxx
fix logic of the (xAOD)XtoVVDecayFilterExtended.cxx to be consistent with what is done for HepMC2 version of the filter, in the current HepMC3 approach one generation of the ancestors was skipped For info @qidong
Edited by Ewelina Maria Lobodzinska