Fixes two segfaults in CAF processing of SBND v10_06_00_09.

[kjplows]

Description

During reprocessing of the SBND Spring BNB+cosmics (prodgenie) MC, a portion of cafmaker jobs failed, reproducibly.
These were tracked down to the following two (as of the writing of this PR) unrelated bugs:

1. Geant4WeightCalc::GetWeight -- there are particles in the MC whose coordinates exit out of the world volume. As an example, tracked down with gdb, a neutron exited out of bounds at negative Y (see below output). This causes the geometry service to return a null pointer for the material associated with that trajectory point, and segfaults immediately after.

testpoint1 = {fCoordinates = {fX = 44902.567134945333, fY = -50000.000000000007, fZ = 14141.128131299527}}
testmaterial1 = 0x0

Fix: Added guard in G4 weight calculator against trajectory points outside world volume.
This does not affect calculations, as points that do not correspond to LAr material do not currently get weighted.
Summoning @jzennamo for review.

2. sbn::GetWallCross -- the calculation assumes there are always two intersections of a line connecting two points and a detector bounding box. This is untrue if one or both of the points are outside the bounding box.
   There is an assert( intersections.size() == 2 ); statement that does not fire, leading to a segfault on the call for intersections[0].

See the attached image, from an example tracked down with gdb -- p0, p1 have coordinates (198.71, 178.94, 518.58) and (197.87, 180.60, 518.98) cm respectively, compared to the detector bounding box defined by [-201.30, 201.30] x [-203.73, 203.73] x [0, 509.40] cm^3.
(The line misses the detector by about 7 cm..)

Fix: Added switch statement to explicitly return caf::kWallNone if zero points. As a bonus, if one intersection, pad the vector with a "second point" same as the first, to make the calculation work. And if somehow the points both lie on an edge of the detector, just use the first two points.

Summoning @sungbinoh for review. In the upcoming develop PR, this fix will be located in FillTrue.cxx.

As this PR does affect CAFs (positively, I should hope!), I am summoning @PetrilloAtWork for review.

Here are some turkey emojis, to help my case for this PR: 🦃🦃🦃
See also #610.

• Have you added a label? (bug/enhancement/physics etc.)
• Have you assigned at least 1 reviewer?
• Is this PR related to an open issue / project?
• Does this PR affect CAF data format? If so, please assign a CAF maintainer as additional reviewer.
• Does this PR require merging another PR in a different repository (such as sbnanobj/sbnobj etc.)? If so, please link it in the description.
• Are you submitting this PR on behalf of someone else who made the code changes? If so, please mention them in the description.

[sungbinoh]

Thank you @kjplows !
The updates look good to me.
I cannot see any issue with updates inGetWallCross to FillTrue.cxx's FillTrueG4Particle.

[PetrilloAtWork]

I recommend to remove the redundant duplication in the second change.
I also mention for your consideration the possibility to fix the first issue by computing in a loop intersection_i, something like:

  if (intersections.empty()) return caf::WallNone; // no intersection

  // get the intersection point closest to p0
  TVector3 closestIntersection;
  double minDistance2 = std::numeric_limits<double>::max();
  for (auto const& point: intersections) {
    double const d2 = (point - p0).Mag2();
    if (d2 > minDistance2) continue;
    minDistance2 = d2;
    closestIntersection = point;
  }

This saves you for having to take decisions.
I save my usual rant against TVector3 for better times.

[PetrilloAtWork]

Thank you for the changes!

[kjplows]

trigger build ci_ref=v10_06_00_06 SBNSoftware/sbndcode@v10_06_00_09 SBNSoftware/sbn*@release/SBN2025A LArSoft/larsoft@LARSOFT_SUITE_v10_06_00_02 LArSoft/larwirecell@LARSOFT_SUITE_v10_06_00_02 LArSoft/lar*@LARSOFT_SUITE_v10_06_00

[FNALbuild]

✔️ CI build for LArSoft Succeeded on slf7 for c14:prof -- details available through the CI dashboard

[FNALbuild]

✔️ CI build for LArSoft Succeeded on slf7 for e26:prof -- details available through the CI dashboard

[FNALbuild]

❌ CI build for SBND Failed at phase build SBND on slf7 for c14:prof -- details available through the CI dashboard

🚨 For more details about the failed phase, check the build SBND phase logs

parent CI build details are available through the CI dashboard

[FNALbuild]

❌ CI build for ICARUS Failed at phase build ICARUS on slf7 for c14:prof -- details available through the CI dashboard

🚨 For more details about the failed phase, check the build ICARUS phase logs

parent CI build details are available through the CI dashboard

[FNALbuild]

⚠️ CI build for SBND Warning at phase ci_tests SBND on slf7 for e26:prof - ignored warnings for build -- details available through the CI dashboard

🚨 For more details about the warning phase, check the ci_tests SBND phase logs

parent CI build details are available through the CI dashboard

[FNALbuild]

❌ CI build for ICARUS Failed at phase ci_tests ICARUS on slf7 for e26:prof - ignored warnings for build -- details available through the CI dashboard

🚨 For more details about the failed phase, check the ci_tests ICARUS phase logs

parent CI build details are available through the CI dashboard