QEE dark photon 2024 conditions

Here the new Dark Photon MC request - since tuppling of MC now forbidden in AP's.

@emrodrig and @jiuzhao please let us know as soon as we can submit the request.

Need to wait for dec files of pi0/eta -> e+e-gamma Dalitz decays to be merged, see lhcb-datapkg/Gen/DecFiles!2048 (merged).

FYI : @johndan

PDG Approval: Comparison with data needed for preparing early measurement \pi^0/ \eta \rightarrow \mu^+ \mu^- \gamma