[FIX] account: avoid base being included twice in group

Create multiple tax and assign them to the same tax group. Now create an
invoice, in the line add all the taxes in the group. Save and click on
"Preview". In the tax recap the tax group will be reported applied on a
total equal to the number of used taxes multiplied by the total of the
product. This append because in the calculation the tax are included
multiple times and not just once per group.

opw-2158989

closes odoo/odoo#42814

X-original-commit: 261c528b87bd8e5b5e4cd0dbaf01c49197bf192c
Signed-off-by: Nicolas Martinelli (nim) <nim@odoo.com>

addons/account/models/account_move.py

@@ -1267,11 +1267,12 @@ class AccountMove(models.Model):
             res = {}
             # There are as many tax line as there are repartition lines
             done_taxes = set()
+            done_groups = set()
             for line in tax_lines:
                 res.setdefault(line.tax_line_id.tax_group_id, {'base': 0.0, 'amount': 0.0})
                 res[line.tax_line_id.tax_group_id]['amount'] += line.price_subtotal
                 tax_key_add_base = tuple(move._get_tax_key_for_group_add_base(line))
-                if tax_key_add_base not in done_taxes:
+                if tax_key_add_base not in done_taxes and line.tax_line_id.tax_group_id not in done_groups:
                     if line.currency_id != self.company_id.currency_id:
                         amount = self.company_id.currency_id._convert(line.tax_base_amount, line.currency_id, self.company_id, line.date)
                     else:
@@ -1279,6 +1280,7 @@ class AccountMove(models.Model):
                     res[line.tax_line_id.tax_group_id]['base'] += amount
                     # The base should be added ONCE
                     done_taxes.add(tax_key_add_base)
+                    done_groups.add(line.tax_line_id.tax_group_id)
             res = sorted(res.items(), key=lambda l: l[0].sequence)
             move.amount_by_group = [(
                 group.name, amounts['amount'],