Fix the RB26/2 bellow being filled twice in the Run 4 beam pipe

This applies the previous commit's fix to PipeRun4.cxx, which carried the same
duplicated wiggle stack.

- The RB26/3 compensator block in PipeRun4.cxx is the same copy of the RB26/2
  positioning code, filling voRB26s2Bellow a second time with the same nodes at
  the same translations.
- RB26s2Bellow therefore held 30 daughters instead of 15, the duplicates being
  RB26s2PlieConn1 x28, RB26s2LowerPlie x15 and RB26s2UpperPlie x14.
- The block is removed. The removed lines are textually identical to the ones
  at PipeRun4.cxx:1782, so every duplicate sat on an existing node.
- RB26s3Bellow is left empty, as it already was, matching Pipe.cxx.

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

Author: sawenzel

Detectors/Passive/src/PipeRun4.cxx

@@ -2165,15 +2165,9 @@ void PipeRun4::ConstructGeometry()
   float zBellowTot = kRB26s3NumberOfPlies * (static_cast<TGeoBBox*>(voRB26s3Wiggle->GetShape()))->GetDZ();
   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 iw = 0; iw < kRB26s2NumberOfPlies; iw++) {
-    float 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));