Validation is blind to the performance of hit reconstruction and FlagBkgHits

[brownd1978]

We need to add ComboHit (and maybe BkgCluster) payload to the nightly validation to be directly sensitive to changes in hit reconstruction and FlagBkgHits. We should remove the distributions of low-level objects coming from SelectRecoMC as those are too highly sculpted by the track reconstruction to be useful.