[FIX] account: prevent excess calls of _get_lines_onchange_currency

That method iterates over move lines:

https://github.com/odoo/odoo/blob/7623a0c771495cd41bf40af37c0d2b6e4beb7cdc/addons/stock_account/models/account_move.py#L16-L18

So, we have O(n^2) complexity at least. It leads to timeout error on invoices
with few hundres products. After this commit it takes 70 seconds to confirm an
invoice with 450 lines:

23527 11.038 56.530
(Number of queries / Query time, sec / Remaining time, sec)

---

https://github.com/odoo/odoo/commit/9e1aec7873a935b287b4b3c5dbc2688acee5422a
opw-2488458

closes odoo/odoo#68797

X-original-commit: 176ecb1239f7e0a8e938de996d174b9c5bf930f4
Signed-off-by: Laurent Smet <smetl@users.noreply.github.com>

addons/account/models/account_move.py

@@ -1267,12 +1267,9 @@ class AccountMove(models.Model):
             total_residual_currency = 0.0
             total = 0.0
             total_currency = 0.0
-            currencies = set()
+            currencies = move._get_lines_onchange_currency().currency_id
 
             for line in move.line_ids:
-                if line.currency_id and line in move._get_lines_onchange_currency():
-                    currencies.add(line.currency_id)
-
                 if move._payment_state_matters():
                     # === Invoices ===
 
@@ -1313,7 +1310,7 @@ class AccountMove(models.Model):
             move.amount_residual_signed = total_residual
             move.amount_total_in_currency_signed = abs(move.amount_total) if move.move_type == 'entry' else -(sign * move.amount_total)
 
-            currency = len(currencies) == 1 and currencies.pop() or move.company_id.currency_id
+            currency = currencies if len(currencies) == 1 else move.company_id.currency_id
 
             # Compute 'payment_state'.
             new_pmt_state = 'not_paid' if move.move_type != 'entry' else False