Fixed faulty logic for NPV retrieval il TrigEventInfoRecorderAlg.cxx

This MR corrects a previous mistake in the way the number of primary vertices was computed in the TLA block of TrigEventInfoRecorderAlg.cxx.

Previously, the condition: privtx->vertexType() == xAOD::VxType::PriVtx was enforced for a vertex to be counted. This would result in every event having exactly NPV=1, which implies that the previous logic would identify the hard scatter vertex, rather than all primary vertices.

A quick check on 2 (!) 2018 EB events shows now NPV = 16 and 19 respectively.

Tagging @cantel and @ayana for review from the JetTrigger signature.