ECAL pn with no ECAL geometry?

[tvami]

Describe the bug

This is more of a question / something to look into in details, but if I run the ecal pn with ldmx-det-v14-8gev-no-cals it produces events. A little bit unintuitive given that there is no ECAL volume to have the ECAL pn to happen on.

To Reproduce
Take https://github.com/LDMX-Software/ldmx-sw/blob/trunk/.github/validation_samples/ecal_pn/config.py
and modify the geometry to ldmx-det-v14-8gev-no-cals

Desired behavior

This might be somehow all fine, but one should run the stepping printout function to see what's happening.

Additional context

Geom introduced in #1424

[EinarElen]

I think a thorough review and overhaul of the filtering system is long overdue, they keep causing issues and are hard to understand. And they are a perf issue #1376