Disable OR flag for MET branches

Fix error encountered with AsgxAODMetNTupleMakerAlg when turning on the overlap removal. Removes the _OR suffix added to the MET branches. Expected since there is no MET collection in the output of the OR sequence https://gitlab.cern.ch/atlas/athena/-/blob/main/PhysicsAnalysis/Algorithms/AsgAnalysisAlgorithms/python/OverlapAnalysisSequence.py#L37

StoreGateSvc                                      WARNING retrieve(const): No valid proxy for object AnalysisMET_NOSYS_OR  of type xAOD::MissingETContainer(CLID 1103569747)
METNTupleMaker_AnalysisMiniTree                     ERROR /atlas/strebler/HHbbtautau/TauAntiTauTest/easyjet/athena/PhysicsAnalysis/Algorithms/AsgAnalysisAlgorithms/Root/AsgxAODMetNTupleMakerAlg.cxx:136 (virtual StatusCode CP::AsgxAODMetNTupleMakerAlg::execute()): Failed to call "evtStore()->retrieve (met, element_itr.first)"

Follow up to !259 (merged)