added Lb_JpsiKsppi,mm=TightCut,KSVtxCut,pKst892,Pc4100cocktail.dec for Pc search
New decfile to complement existing: https://gitlab.cern.ch/lhcb-datapkg/Gen/DecFiles/-/blob/v30r62/dkfiles/Lb_JpsiKsppi,mm=TightCut,KSVtxCut,cocktail.dec
Uses a dummy Pc(4100) -> Jpsi p near-threshold resonance.