cmssw: Do we still need to support the muon reco duplicate mitigation in PhysicsTools/PatUtils?

While reviewing PR #33307 it was evident that we keep spending time and effort in maintaining some code which is quite likely not needed any more in CMSSW:

• PhysicsTools/PatUtils/python/tools/muonRecoMitigation.py assumes the existence of a PFCandPtrProjector plugin, which is not found anywhere in CMSSW, not even in 9_1_X (which is the release where this config was introduced with #18165)
• That muon reco duplicate mitigation is only required by corMETFromMuonAndEG, which is defined in PhysicsTools/​PatUtils/​python/​tools/​corMETFromMuonAndEG.py and only called by PhysicsTools/PatAlgos/python/slimming/extraSlimmedMETs_MuEGFixMoriond2017.py,;which according to the name is quite likely not in use any more
• Moreover, muCorrection=False in there, and therefore this muonRecoMitigation wasn’t actually ever accessed even from there.

The main point is the following: do we still need to support the muon reco duplicate mitigation in corMETFromMuonAndEG? Do we need to keep supporting corMETFromMuonAndEG at all? Couldn’t they be safely removed from the release?

@zdemirag @kirschen @lathomas @ahinzmann @mariadalfonso