[MCH] add cut random fraction setting for the cases with and without ITS

Two new environment variables are introduced to provide the fraction of
rejected MCH events separately for the cases where ITS is either included
(CUT_RANDOM_FRACTION_MCH_WITH_ITS) or excluded (CUT_RANDOM_FRACTION_MCH_NO_ITS)
from the data taking.

The CUT_RANDOM_FRACTION_MCH variable, as well as the two new ones, can still
be overridden by setting them explicitly in the shell environment,
therefore the changes are backward compatible.

Author: aferrero2707

prodtests/full-system-test/dpl-workflow.sh

@@ -352,7 +352,12 @@ if has_processing_step MUON_SYNC_RECO; then
     elif [[ $RUNTYPE == "PHYSICS" && $BEAMTYPE == "pp" ]] || [[ $RUNTYPE == "COSMICS" ]]; then
       CONFIG_EXTRA_PROCESS_o2_mch_reco_workflow="MCHTracking.chamberResolutionX=0.4;MCHTracking.chamberResolutionY=0.4;MCHTracking.sigmaCutForTracking=7.;MCHTracking.sigmaCutForImprovement=6.;"
     fi
-    has_detector_reco ITS && [[ $RUNTYPE != "COSMICS" ]] && CONFIG_EXTRA_PROCESS_o2_mch_reco_workflow+="MCHTimeClusterizer.irFramesOnly=true;"
+    if has_detector_reco ITS && [[ $RUNTYPE != "COSMICS" ]]; then
+        CONFIG_EXTRA_PROCESS_o2_mch_reco_workflow+="MCHTimeClusterizer.irFramesOnly=true;"
+        [[ -z ${CUT_RANDOM_FRACTION_MCH:-} ]] && CUT_RANDOM_FRACTION_MCH=${CUT_RANDOM_FRACTION_MCH_WITH_ITS:-}
+    else
+        [[ -z ${CUT_RANDOM_FRACTION_MCH:-} ]] && CUT_RANDOM_FRACTION_MCH=${CUT_RANDOM_FRACTION_MCH_NO_ITS:-}
+    fi
     [[ ! -z ${CUT_RANDOM_FRACTION_MCH:-} ]] && CONFIG_EXTRA_PROCESS_o2_mch_reco_workflow+="MCHTimeClusterizer.rofRejectionFraction=$CUT_RANDOM_FRACTION_MCH;"
     CONFIG_EXTRA_PROCESS_o2_mch_reco_workflow+="MCHStatusMap.useHV=false;MCHDigitFilter.statusMask=3;"
   fi