Fix old-style ISF_PionATLFAST3_QS_Geant4Selector configuration
Should cut on MaxEkin rather than MaxMom to match 21.0 and CA-based configuration. (Same fix as for ISF_PionATLFAST3Geant4Selector in !49176 (merged).)
This should fix the test_RUN3Sym_ATLFAST3MT_QS_ttbar_CAvsCG.sh ART job.
Should fix ATLASSIM-5560