[IMP] sale_payment: avoid defining out-of-the-blue context keys when odoo behavior is sufficient

As what has been implemented is basically a default, let us use the default
mechanism of odoo.

addons/account/models/account_invoice.py

@@ -1387,8 +1387,6 @@ class AccountInvoice(models.Model):
             'payment_difference_handling': writeoff_acc and 'reconcile' or 'open',
             'writeoff_account_id': writeoff_acc and writeoff_acc.id or False,
         }
-        if self.env.context.get('tx_currency_id'):
-            payment_vals['currency_id'] = self.env.context.get('tx_currency_id')
 
         payment = self.env['account.payment'].create(payment_vals)
         payment.post()

addons/sale_payment/models/payment.py

@@ -87,7 +87,8 @@ class PaymentTransaction(models.Model):
                     _logger.warning('<%s> transaction completed, could not auto-generate payment for %s (ID %s) (no journal set on acquirer)',
                                     self.acquirer_id.provider, self.sale_order_id.name, self.sale_order_id.id)
                 self.acquirer_id.journal_id = default_journal
-                created_invoice.with_context(tx_currency_id=self.currency_id.id).pay_and_reconcile(self.acquirer_id.journal_id, pay_amount=created_invoice.amount_total)
+                # TDE Note: in post-v11 we could probably add an explicit parameter + update account.payment tx directly at creation, not afterwards
+                created_invoice.with_context(default_currency_id=self.currency_id.id).pay_and_reconcile(self.acquirer_id.journal_id, pay_amount=created_invoice.amount_total)
                 if created_invoice.payment_ids:
                     created_invoice.payment_ids[0].payment_transaction_id = self
         else: