Sweeping McEventCollection_p7 persistent version and associated TP converter into 23.0
This merge request sweeps the McEventCollection_p7 persistent version and the associated TP converter into 23.0
for forward compatibility with future main branch releases.
See also merge request atlas/Athena!65249 which added these classes into the main branch.
McEventCollection_p7 will use the new GenParticle/GenVertex status scheme natively, whereas the transient objects in 23.0
and the McEventCollection_p6 persistent version written out by this branch will always use the current (old) status scheme.
Therefore the version of the McEventCollection_p7 TP converter for this branch has been adapted to convert status values from
the new scheme to the old scheme during P->T conversion.
NB The changes in this MR should be excluded from sweeps to main to avoid conflicts and un-intended behaviour in the main branch.
Further changes will be made to McEventCollection_p7 and the corresponding TP converters in the next few months as the migration away from GenParticle/GenVertex barcodes continues.