[FIX] account_accountant: fix multiple liquidity lines

When multiple liquidity lines exist on an account.move (occuring before
14.0), the bank reconciliation widget crashes. Taking the sum of the
`amount` and `amount_currency` solves it.

opw-3202392

closes odoo/odoo#114204

X-original-commit: 564f91be019a1f5fe737a01218972dfd9d74d7c8
Signed-off-by: Laurent Smet <las@odoo.com>
Signed-off-by: Julien Van Roy <juvr@odoo.com>

addons/account/models/account_bank_statement_line.py

@@ -492,9 +492,9 @@ class AccountBankStatementLine(models.Model):
         return (
             transaction_amount,
             transaction_currency,
-            liquidity_line.amount_currency,
+            sum(liquidity_line.mapped('amount_currency')),
             liquidity_line.currency_id,
-            liquidity_line.balance,
+            sum(liquidity_line.mapped('balance')),
             liquidity_line.company_currency_id,
         )