Fixes to validation for NTUP_PHYSVAL

Making sure that the events of NTUP_PHYSVAL are counted correctly.

At the same time, fixing the corruption check which was crashing on any files that are not fairly standard POOL files or derivations; see for example the crash here:

https://bigpanda.cern.ch/art/test/DerivationFrameworkPhysicsValidationART/test_mc21PHYSVAL_DAOD_NTUP_HIST.sh/?ntag_full=2024-07-03T2101&branch=main/Athena/x86_64-el9-gcc13-opt