Fix muon link to charged flow element
requested to merge atlas-particleflow-software/athena:dev/Matt/UpgradeMuonAssociationLinks into master
This merge request should fix an issue observed in the FlowElement linkers to muons, ignoring the case where a muon is identified as forward muon (so associated tracks will be ignored in the linker alg) or authored by the MuonStaco algorithm in the muon match to charged flow element routine.