Data race found in QED tests

[lucafedeli88]

Hi! I am currently trying to expand the coverage of the clang-sanitizers tests in CI (#5280)
In particular, I've added some QED tests and the thread sanitizer seems to find a data race:
https://github.com/ECP-WarpX/WarpX/actions/runs/10900721122/job/30248957047?pr=5280

The issue seems to concern the line

for (WarpXParIter pti(*pc_source, lev, info); pti.isValid(); ++pti)

in doQedBreitWheeler and doQedQuantumSync