JetForwardJvtTool: Add flag to read in instead of calculate fJVT

This allows the JetForwardJvtTool to be used on DAOD's in release 22 where Track MET is not stored but the fJVT for primary vertex is.

Reconstruction/Jet/JetMomentTools/JetMomentTools/JetForwardJvtTool.h

@@ -81,6 +81,7 @@
     Gaudi::Property<double> m_jetScaleFactor{this, "JetScaleFactor", 0.4, "Jet scale factor"};
     Gaudi::Property<double> m_fjvtThresh{this, "FjvtThresh", 15e3, "FJVT threshold"}; //15GeV->92%,11GeV->85%
     Gaudi::Property<bool> m_tightOP{this, "UseTightOP", false, "Use tight (true) or loose (false)"};
+    Gaudi::Property<bool> m_recalculateFjvt{this, "RecalculateFjvt", true, "Recalculate Fjvt or use stored value"}; 
     mutable std::vector<TVector2> m_pileupMomenta;
     mutable size_t m_pvind = 0UL;
     void getPV() const;