[FIX] l10n_fr_fec: new line

Commit 5dfb6e39af added the new line
characters at the end of each line but the last one.

However, it does so by adding a new element in the row: therefore, 19
columns are created instead of the 18 required.

We add the new line character at the end of the last element of the row.

opw-2000429

closes odoo/odoo#33571

Signed-off-by: Nicolas Martinelli (nim) <nim@odoo.com>

addons/l10n_fr_fec/wizard/account_fr_fec.py

@@ -389,7 +389,7 @@ class AccountFrFec(models.TransientModel):
         rows_length = len(rows)
         for i, row in enumerate(rows):
             if not i == rows_length - 1:
-                row.append(lineterminator)
+                row[-1] += lineterminator
             writer.writerow(row)
 
         fecvalue = fecfile.getvalue()