Updated eFEX monitoring histos to have low/high pt cuts
requested to merge l1calo-run3-simulation/athena:22.0-l1calo-eFEX-monitoring-histo-updates into 22.0
Updated files EfexMonitorAlgorithm.(cxx/h/py) to create histos with two different Et cuts - currently set to 0 (no cut) and 15GeV.