Protections against high pT pions becoming tracker-driven only gedGsfElectrons

@dbenedet please add plots

This pull request contains an update to gedGsfElectron producer to harmonize the pre-selection of tracker-driven-only gedGsfElectrons above 50 GeV.

In private tests we saw an improvement in the fake rate for tracker-driven-only GSF electrons and no change in efficiency for electrons from Z>ee.