Add jFEX/gFEX L1 & large-R HLT chains

I added the respective jFEX and gFEX large-R L1 and HLT chains to the legacy jet monitoring tool which have been discussed here: https://its.cern.ch/jira/browse/ATR-22322 Also fixed a compiler warning, and the small-R L1 jFEX "key" variable.

The L1_gLJ100 histograms are not filled due to the association issue discussed below (will be followed up on ATR-22412). Tagging @jbossios @bcarlson