activelayer in V1
In sed_MUSTANG_erosion (V1), see https://gitlab.inria.fr/croco-ocean/croco/-/blob/dev_2022_mustang/MUSTANG/sed_MUSTANG.F90#L3532
In this case, profsed is always equal to zero if k=ksmax+1 in the do loop line 3528
Remove active layer in V1