[FIX] point_of_sale: flattening only group of taxes when creating amls

Revision 89c63096cb95f10f8bb3770e10d330aa904ac159 fixed the creation
of the taxes applied to account move lines when validating a pos session

The fix though overlooked two things:
- protection against recursivity
(nothing prevents a group of taxes to have a grand-parent as one of its children)
- the fact that when converting a group of taxes into a regular computed one,
the field children_ids is never reset

Those two caveats provoked a "max recursivity error" in python within the right conditions

This commit protects the recursive process from the two issues, and there is no traceback

OPW 816163

0 files changed, 0 insertions, 0 deletions