[Futurev4] Propagate the removal of getDetector()

This MR fixes the lhcb-gaussino slot with

Sim/DD4hepCnv/src/component/LHCbDD4hepCnvSvc.cpp:21:82: error: 'struct LHCb::Det::LbDD4hep::IDD4hepSvc' has no member named 'getDetector'

by removing getDetector() dependency from Gauss-on-Gaussino. The changes were first introduced here: LHCb!2998 (merged)