Make EventAuxInfo_v1 data members public
This MR sweeps the change in !23228 (merged) to 21.X branches. Essentially, we're making the EventAuxInfo_v1
data members public so that we can access them in PyROOT
easily. After this MR goes in, we should be able to run diff-root
with the option --order-trees
to compare Athena
results against AthenaMP
results.