Add a new G4UserStepping Action: FixG4CreatorProcess
This stepping action is necessary to make sure that the creator process of the secondary tracks of the current step is the same as the one that limited the step. When activating some 'wrapper' processes like the G4GammaGeneralProcess or G4HepEm these might be different and lead to errors in the code.
This MT should fix the mismatches seen in the physics validation plots of the TRT when activating the G4GammaGeneralProcess.
It can be tested in a Sim_tf.py job using adding the following preExec:
--preExec 'EVNTtoHITS:simFlags.OptionalUserActionList.addAction("G4UA::FixG4CreatorProcessTool")'
A new preInclude file preInclude.G4GammaGeneralProcess.py
has been introduced, in order to activate the G4GammaGeneralProcess and at the same time
use the new stepping action to set correctly the Creator Process.