migrate G4EmProcessOptions.hh to G4EmParameters.hh
Migration to use directly G4EmParameters instead of G4EmProcessOptions as advised by Geant4 people.
It is potentially a breaking change because it merges two properties of hysicsListToolBase into one. This was advised decided upon discussion in ATLASSIM-3967.
With a LXR search only one client using these properties was found and the settings were commented out. This MR adds an additional comment as a warning.