[QEE] prompt_dielectron_with_brem make BPVFDCHI2 cut optional

Reported here: !2886 (comment 7687719)

Changes:

By default, standard_particles.make_prompt_dielectron_with_brem includes a cut on FD of the dielectron: F.BPVFDCHI2(pvs) > 30. This would mean it's detached and not prompt?

QEE's DiElectron_PersistPhotons seem to be the only users of these standard_particles, and they overwrite this cut for both prompt and detached DiEs with F.BPVFDCHI2(pvs) >0. This is still not entirely correct, as it removes the ==0 events.

Fixed the former via < 30 by default. If bpvvdchi2==None, then no cut is applied instead -> leaves performance of Prompt DiElectrons alone.

Local Evaluations.

With these changes:
DiElectron turbo lines on 10k events: mdf size = 1.1MB and #PassedEvents = 275.
Rate = 31.4 kHz
BW = 125 MB/s

Without these changes: DiElectron turbo lines on 10k events: mdf size = 1.1MB and #PassedEvents = 275.
Rate = 31.4 kHz.
BW = 125 MB/s.

Most Recent CI-test:

!3134 (comment 7698745)

Total rate = 282.1 kHz - change of 0.00% vs. reference.
Total bandwidth = 14.6 GB/s - change of 0.00% vs. reference.
New lines added: 0.
Lines with rate of 0 Hz: 1129.
Lines with rate > 1000 Hz: 90.
✅ All sub-jobs in this test exited successfully.

Conclusion:

No change as expected 🎇

ToDo:

• Verify locally, as we expect, very little change to DiElectron lines from this change.
• Verify if other lines use these builders.
  • Only QEE uses the standard_particles.prompt_dielectron_with_brem builders. RD's uses a very similar one but without BPVFDCHI2.