Add to PhotonAnalyzer and ZToMuMuGammaAnalyzer the histogram with Nvtx and the sigmaE/E vs Nvtx
Fix crash in HI sequence. Was due to accessing the Offline vertex collection, not present in the HI reco
Merge pull request #3143 from nancymarinelli/egmGedDQMOfflineUpdatesFor7XX_3

DQM -- DQMOffline/EGamma: Add to PhotonAnalyzer and ZToMuMuGammaAnalyzer the histogram with Nvtx and the sigmaE/E vs Nvtx