Fix the RB26/2 bellow being filled twice in the beam pipe

This removes a duplicated wiggle stack in the beam pipe geometry, which
placed 57 volumes exactly on top of identical copies of themselves.

- The RB26/3 compensator block carried a copy of the RB26/2 positioning
  code that was never renamed, so it filled voRB26s2Bellow a second time
  with the same nodes at the same translations.
- RB26s2Bellow therefore held 30 daughters instead of 15.
- The duplicates were RB26s2PlieConn1 x28, RB26s2LowerPlie x15 and
  RB26s2UpperPlie x14.
- The block is removed. Nothing else changes: a walk over the PIPE
  geometry composing every world matrix gives 1152 leaf placements before
  and 1095 after, with the set of distinct (volume, world transform)
  pairs identical at 1071 in both.
- CheckOverlaps(0.001) reports the same single pre-existing overlap
  before and after. It could not have flagged this defect: exactly
  coincident copies of one volume have a zero-extent boundary crossing,
  which the sampling never resolves as an overlap.
- RB26s3Bellow is left empty, as it already was. Giving it the RB26/3
  wiggle stack changes the material budget and is a separate fix.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Author: sawenzel

Detectors/Passive/src/Pipe.cxx

@@ -2300,15 +2300,9 @@ void Pipe::ConstructGeometry()
   TGeoVolume* voRB26s3Bellow =
     new TGeoVolume("RB26s3Bellow", new TGeoTube(kRB26s3BellowRi, kRB26s3BellowRo, zBellowTot), kMedVacHC);
 
-  // Positioning of the volumes
-  z0 = -kRB26s2BellowUndL / 2. + kRB26s2ConnectionPlieR;
-  voRB26s2Bellow->AddNode(voRB26s2WiggleL, 1, new TGeoTranslation(0., 0., z0));
-  z0 += kRB26s2ConnectionPlieR;
-  zsh = 4. * kRB26s2PlieR - 2. * kRB26s2PlieThickness;
-  for (Int_t iw = 0; iw < kRB26s2NumberOfPlies; iw++) {
-    Float_t zpos = z0 + iw * zsh;
-    voRB26s2Bellow->AddNode(voRB26s2Wiggle, iw + 1, new TGeoTranslation(0., 0., zpos - kRB26s2PlieThickness));
-  }
+  // RB26s3Bellow is left without plies. The wiggle stack that stood here was a copy of the
+  // RB26/2 code and filled voRB26s2Bellow a second time; filling it with the RB26/3 wiggle
+  // would change the material budget and is a separate fix.
 
   voRB26s3Compensator->AddNode(voRB26s3Bellow, 1,
                                new TGeoTranslation(0., 0., kRB26s3WeldingTubeLeftL + zBellowTot));