[FIX] account: Wrong amount due when reconciling with refund

Steps to reproduce the bug:
- Let's consider the following currency rates: 1.00 for USD and 0.50 for EUR
- Create invoice I with the same currency of your company (USD) and amount due = 100$
- Validate I
- Create refund R with  a diffenrent currency of your company (EUR) and amount due = 1€
- Validate R
- Reconcile R with I

Bug:

The amount due of I was 196$ instead of 98$

PS: The root of this issue was coming from function assign_outstanding_credit that was called when
reconciling R with I. This function changes the currency_id and the amount_currency of the account move line.
So the function _amount_residual defined on model account.move.line was triggered as
the currency_id was changed. In _amount_residual, the residual_amount_currency was computed.

Forward-port up to saas-11.3

Closes #36252

opw:2062103

closes odoo/odoo#36412

Signed-off-by: Simon Goffin (sig) <sig@openerp.com>

addons/account/models/account_invoice.py

@@ -114,8 +114,10 @@ class AccountInvoice(models.Model):
             if line.currency_id == self.currency_id:
                 residual += line.amount_residual_currency if line.currency_id else line.amount_residual
             else:
-                from_currency = (line.currency_id and line.currency_id.with_context(date=line.date)) or line.company_id.currency_id.with_context(date=line.date)
-                residual += from_currency.compute(line.amount_residual, self.currency_id)
+                if line.currency_id:
+                    residual += line.currency_id.with_context(date=line.date).compute(line.amount_residual_currency, self.currency_id)
+                else:
+                    residual += line.company_id.currency_id.with_context(date=line.date).compute(line.amount_residual, self.currency_id)
         self.residual_company_signed = abs(residual_company_signed) * sign
         self.residual_signed = abs(residual) * sign
         self.residual = abs(residual)