Flagging off-shell photon and mis-classified material conversion

A very simple conversion reconstruction (circles and mass) added on top of electron reconstruction can help to decrease the fake rate from internal conversion and early hoton conversion in the material. This is done in the piece of code added here. A integer flag is added to the electron smart sliming list. This is for 21.2 (while this kind of identification is expected to be done more upstream in the reco/ID for rel22)