Geant4GFlashShowerModel: remove wrong unit conversions from particleBound properties

[andresailer]

BEGINRELEASENOTES

• Geant4GFlashShowerModel: remove wrong unit conversions from particleBound properties. Caused particle bounds to be off by 1e3 when GEANT_UNITS were enabled.

ENDRELEASENOTES

The reason why the test failed was that nan showed up in the position of the hit. This nan comes originally from here

https://github.com/Geant4/geant4/blob/dda54bbdcfe0cc76177eaa03a657592aac0b1eb8/source/parameterisations/gflash/src/GFlashHomoShowerParameterisation.cc#L177

Why we only saw this sometimes is not clear. If this is related to the particle bounds, or if we were just lucky before, or something systematic in the functions.

[github-actions[bot]]

Test Results

   14 files     14 suites   6h 36m 29s :stopwatch:   363 tests   363 :white_check_mark: 0 :zzz: 0 :x: 2 496 runs  2 496 :white_check_mark: 0 :zzz: 0 :x:

Results for commit ab79dd7d.