[FIX] account: invoice compute tax group amount correctly grouped

Before this commit, when printing an invoice, the taxes were grouped
by their tax group (NOT by their parent tax)
Summing the base of each tax in the process.

This was largely insufficient, as tax groups can have taxes
with different rates or computation method within them

The summing of the base of each tax for reach tax group was in this case plain wrong

This commit aims at grouping by
group > computation method > amount

Which makes more sense

OPW 1947202
OPW 1945353

closes odoo/odoo#31617

Signed-off-by: Lucas Perais (lpe) <lpe@odoo.com>

addons/account/models/account_invoice.py

@@ -1559,12 +1559,14 @@ class AccountInvoice(models.Model):
             fmt = partial(formatLang, invoice.with_context(lang=invoice.partner_id.lang).env, currency_obj=currency)
             res = {}
             for line in invoice.tax_line_ids:
-                res.setdefault(line.tax_id.tax_group_id, {'base': 0.0, 'amount': 0.0})
-                res[line.tax_id.tax_group_id]['amount'] += line.amount_total
-                res[line.tax_id.tax_group_id]['base'] += line.base
-            res = sorted(res.items(), key=lambda l: l[0].sequence)
+                tax = line.tax_id
+                group_key = (tax.tax_group_id, tax.amount_type, tax.amount)
+                res.setdefault(group_key, {'base': 0.0, 'amount': 0.0})
+                res[group_key]['amount'] += line.amount_total
+                res[group_key]['base'] += line.base
+            res = sorted(res.items(), key=lambda l: l[0][0].sequence)
             invoice.amount_by_group = [(
-                r[0].name, r[1]['amount'], r[1]['base'],
+                r[0][0].name, r[1]['amount'], r[1]['base'],
                 fmt(r[1]['amount']), fmt(r[1]['base']),
                 len(res),
             ) for r in res]