Remove MM SimHits with 0 kinetic energy
The Micromegas digitization was updated in !53113 (merged) to ignore HITS with 0 kinetic energy. In !52947 (closed) discussing some critical MM issues, @jchapman suggested we modify the MM G4 simulation to simply not save SimHits with 0 kinetic energy to save resources. this MR changes the MM G4 simulation to not save the SimHits with 0 kinetic energy.