Change in menu printout for MGonly chains

There is a bug in one of the debug messages for MuGirl only setup muon menu definition (ATR-16181).
This printout is actually not needed, nor are several others, so they (and some variables that are also irrelevent for this case) have been removed.
Tested successfully with:

trigtest.pl --cleardir --test AthenaTrigRDO_MC_pp_v7 --rundir AthenaTrigRDO_MC_pp_v7 --conf TriggerTest.conf
trigtest.pl --cleardir --test HLT_physicsV7 --rundir HLT_physicsV7 --conf TrigP1Test.conf