[IMP] hr: check employees only alias restriction independently of record existence

Commit 78ac6de5 refactored methods checking alias security on the
routing found for a given destination address. Indeed if a routing is found
linked to an alias a security check is performed according to the restriction
defined on the alias itself.

HR module adds the 'employees only' restriction. A bug has been introduced
in the mentioned commit concerning employees-based aliases. Indeed a condition
on having a recordset has been added (self.ids, changed to record.ids at
20d80250). This condition is actually not necessary as checking the
email author is linked to an existing employee has nothing to do with the
alias being linked to a record or creating new record.

This may causes issues notably using employees-restricted aliases in
expense application. Indeed you could use aliases to create new expenses
for employees and you could have issues with this condition.

This commit is linked to task ID 1829860 and ID 35093. Closes #22960 .

addons/hr/models/mail_alias.py

@@ -14,7 +14,7 @@ class MailAlias(models.AbstractModel):
     _inherit = 'mail.alias.mixin'
 
     def _alias_check_contact_on_record(self, record, message, message_dict, alias):
-        if alias.alias_contact == 'employees' and record.ids:
+        if alias.alias_contact == 'employees':
             email_from = tools.decode_message_header(message, 'From')
             email_address = tools.email_split(email_from)[0]
             employee = self.env['hr.employee'].search([('work_email', 'ilike', email_address)], limit=1)