Avoid complaint about unreacheable statement (NVCC)

3 jobs for canal/CudaMultiUnion in 10 minutes and 8 seconds (queued for 4 seconds)
latest
Status Name Job ID Coverage
  Build
failed clang-format #3911301

00:01:51

passed code_checks #3911302

00:10:08

 
  External
failed jenkins

00:16:30

 
Name Stage Failure
failed
clang-format Build
 }; // end Loop Helper
-}
-} // End global namespace
+} // namespace VECGEOM_IMPL_NAMESPACE
+} // namespace vecgeom

#ifndef __clang__
#pragma GCC diagnostic pop
ERROR: Job failed: exit code 1