tauRecTools: decorate ClusterTotalEnergy in MvaTESVariableDecorator
In TauJetRNNUtils, we need to calculate the ratio of FIRST_ENG_DENS and ClustersMeanFirstEngDens. Thise requires the calcalation of ClusterTotalEnergy as ClustersMeanFirstEngDens is already divied by it. Since this variable is already calculated in MvaTESVariableDecorator, we just decorate this variable to tau to avoid duplicate calculation.