[FIX] account: amount by group adapt to repartition

Before this commit, when printing an invoice that has at least
one tax which is part of a tax group and some repartition lines

On the invoice pdf the group of tax contained twice the base amount for that
tax

After this commit, the tax group contains the base only once

OPW 2073989

closes odoo/odoo#37226

Signed-off-by: oco-odoo <oco-odoo@users.noreply.github.com>