[FIX] account: Search res.partner.bank before creating it

- Import 2 bank statement lines having acc_number set but no res.partner.bank having this account
number.
- Reconcile the first one with a line: a res.partner.bank is created.
- Reconcile the second one with a line: UserError('Account number must be unique!')

addons/account/models/account_bank_statement.py

@@ -657,7 +657,13 @@ class AccountBankStatementLine(models.Model):
 
         #create the res.partner.bank if needed
         if self.account_number and self.partner_id and not self.bank_account_id:
-            self.bank_account_id = self.env['res.partner.bank'].create({'acc_number': self.account_number, 'partner_id': self.partner_id.id}).id
+            bank_account = self.env['res.partner.bank'].search(
+                [('acc_number', '=', self.account_number), ('partner_id', '=', self.partner_id.id)])
+            if not bank_account:
+                bank_account = self.env['res.partner.bank'].create({
+                    'acc_number': self.account_number, 'partner_id': self.partner_id.id
+                })
+            self.bank_account_id = bank_account
 
         counterpart_moves.assert_balanced()
         return counterpart_moves