FATRAS: update parent parameters after brem
FATRAS parameters were not updated after brem, this MR fixes it.
- The implementation of brem parameters update is the same way as for the update after ionization/MS
- Changes discussed at FastChain MTG: https://indico.cern.ch/event/1041710/
- This fixes energy non-conservation in case of brem, @tcuhadar : will have visible effects on eg electron spectra
- 10-event test run log: /afs/cern.ch/work/l/lmijovic/public/sim/mr/brem_fix_43748