Treating ions in ddsim

[michael-pitt]

Is your feature request related to a problem? Please describe.
MC Generators with ions at the final state (e.g. BeAGLE #92) cannot use DD4hep

Describe the solution you'd like
It seems that the AIDASoft/DD4hep#920 should solve the problem.

Describe alternatives you've considered
For now, the only workaround is to change the status of the ions in the hepmc files (eic/eic-smear#22) so that when ddsim is executed, these ions will not be handled to G4.

@wdconinc @KongTu @kkauder

[wdconinc]

Confirming that #920 resolves this problem on a sample file as attached. [Nevermind, I can't easily attach a file I'm accessing over ssh from my phone.] @michael-pitt this refers to collision_Q2_min_max_y_min_max_Shd3_ShdFac=1.32_Alldiff9193_Jleptdecay_numev.hepmc