make 410470 the default also for Pythia8
Makes it more compatible with the https://gitlab.cern.ch/atlas/athena/-/blob/21.2/PhysicsAnalysis/Algorithms/FTagAnalysisAlgorithms/python/FTagAnalysisSequence.py. The code was crashing if Pythia8
was specified for the generator sequence, while it worked for the FTAG sequence.
Do we need to port this into master as well?