- Calls the suitable function in PMMG_computePrilen when an aniso metric
 is provided with a specific metric storage at ridges (metRidTyp==1)
  - Check if metric is allocated before computing the edge lengths (to avoid memory errors)
 but inside the `MMG3D|PMMG_computePrilen` functions to be able to differentiate the cases where:
    - computePrilen fails due to memory error
    - We have a metric on at least one MPI proc so we can compute the edge lengths
    - We don't have any metric (and we cannot compute the edge length histo). In this case and
      with a centralized mesh on 1 proc and -v 10 verbosity, we were previously printing infinit edge lengths.

It makes the PMMG_prilen function callable everywhere in the software.

…subscribe command line option support.