[FIX] account: fix TypeError for currency in journal items

If applied, this commit will solve the issue of unsupported operand type in
journal item(s) when currency is not set.

Steps to produce:
- Accounting > Journal Entries > Create new entry.
- Add a line in Journal Items and remove the currency from that line.
- Save > Error will be generated.

Fix this issue by calling the compute of the currency when the currency is not
available.

sentry - 4069681536

closes odoo/odoo#125661

X-original-commit: 7163134b397e113c10936af908bdfebef2336d67
Signed-off-by: Florian Gilbert (flg) <flg@odoo.com>
Signed-off-by: Parth Solanki (paso) <paso@odoo.com>

addons/account/models/account_move_line.py

@@ -634,12 +634,15 @@ class AccountMoveLine(models.Model):
                 date=date,
             )
         for line in self:
-            line.currency_rate = get_rate(
-                from_currency=line.company_currency_id,
-                to_currency=line.currency_id,
-                company=line.company_id,
-                date=line.move_id.invoice_date or line.move_id.date or fields.Date.context_today(line),
-            )
+            if line.currency_id:
+                line.currency_rate = get_rate(
+                    from_currency=line.company_currency_id,
+                    to_currency=line.currency_id,
+                    company=line.company_id,
+                    date=line.move_id.invoice_date or line.move_id.date or fields.Date.context_today(line),
+                )
+            else:
+                line.currency_rate = 1
 
     @api.depends('currency_id', 'company_currency_id')
     def _compute_same_currency(self):