Added missing cerr CUDA guards.
Previous MR making uniform the printing system overlooked some errors in the CUDA build: https://lcgapp-services.cern.ch/cdash/index.php?project=VecGeom&date=2023-07-18
Previous MR making uniform the printing system overlooked some errors in the CUDA build: https://lcgapp-services.cern.ch/cdash/index.php?project=VecGeom&date=2023-07-18