[FIX] l10n_it_edi: imap seen/unseen flag more compatible

In 7dd5437a65 the usage of imagelib was changed to match the one of
general fetchmail so the flag sent to IMAP server was (\Seen) and not
\Seen which is often accepted but not always.

From recent reports, it seems that the method `uid` and `store` may have
some difference (base on using message-id rather than UID) so this
commit is reverting 7dd5437a65 and using the parenthesis around the flag
explicitely.

opw-2853609

closes odoo/odoo#93158

X-original-commit: 550f9e77625a7917bffd693f18aafe10a04276c9
Signed-off-by: Nicolas Lempereur (nle) <nle@odoo.com>

addons/l10n_it_edi/models/ir_mail_server.py

@@ -84,9 +84,9 @@ class FetchmailServer(models.Model):
 
                     # To leave the mail in the state in which they were.
                     if "Seen" not in data[1].decode("utf-8"):
-                        imap_server.store(uid, '+FLAGS', '\\Seen')
+                        imap_server.uid('STORE', uid, '+FLAGS', '(\\Seen)')
                     else:
-                        imap_server.store(uid, '-FLAGS', '\\Seen')
+                        imap_server.uid('STORE', uid, '-FLAGS', '(\\Seen)')
 
                     # See details in message_process() in mail_thread.py
                     if isinstance(message, xmlrpclib.Binary):