[PWGDQ] fix match type assignment in ML training data producer

The match type assigned to candidate MFT-MCH matches in the ML training
data producer task was wrongly set to "fake" in cases where the MCH track
is pairable but the corresponding MFT track does not have an associated MC
particle. In such cases the match type is now correctly assigned as "wrong".

Author: aferrero2707

PWGDQ/Tasks/mftMchMatcher.cxx

@@ -550,6 +550,9 @@ struct mftMchMatcher {
   template <class TMCH, class TMFTs>
   bool isDecay(TMCH const& mchTrack, TMFTs const& mftTracks)
   {
+    if (!mchTrack.has_mcParticle()) {
+      return false;
+    }
     const auto& mchMcParticle = mchTrack.mcParticle();
 
     const auto& mchMotherParticles = mchMcParticle.template mothers_as<aod::McParticles>();
@@ -589,12 +592,6 @@ struct mftMchMatcher {
     auto const& mchTrack = muonTrack.template matchMCHTrack_as<TMUONS>();
     auto const& mftTrack = muonTrack.template matchMFTTrack_as<TMFTS>();
 
-    if (!mchTrack.has_mcParticle() || !mftTrack.has_mcParticle()) {
-      // if either the MCH or the MFT tracks are fakes (not associated to any MC particles)
-      // we consider the match as fake
-      return (isBestMatch ? kMatchTypeFakeLeading : kMatchTypeFakeNonLeading);
-    }
-
     bool isPaired = isPairedMuon(mchTrack.globalIndex(), matchablePairs);
     std::pair<int64_t, int64_t> matchPair{mchTrack.globalIndex(), mftTrack.globalIndex()};
     bool isTrueMatch = std::find(matchablePairs.begin(), matchablePairs.end(), matchPair) != matchablePairs.end();