Fix H3L injection scheme in Pb--Pb (#2075)

Author: fmazzasc

MC/config/PWGLF/ini/GeneratorLFHypertritonPbPbGap.ini

@@ -1,6 +1,6 @@
 [GeneratorExternal]
 fileName=${O2DPG_MC_CONFIG_ROOT}/MC/config/PWGLF/pythia8/generator_pythia8_longlived_gaptriggered.C
-funcName=generateLongLivedGapTriggered({1010010030}, 0, 20)
+funcName=generateLongLivedGapTriggered({1010010030}, 1, 20)
 
 [GeneratorPythia8]
 config=${O2_ROOT}/share/Generators/egconfig/pythia8_hi.cfg