[FIX] mail: ensure case insensitive check when (de)activating blackli…

…st records

Now that blacklist records are set as lower case be sure all checks in
blacklist are done accordingly by using the sanitizer before comparing
email adresses.

This commit is related to task ID 33224 (original blacklist implementation
done for v12) and its PR odoo#25966 as well as task ID 1889703 (tests and fixes)
and its PR odoo#27330. Done with collaboration of @dbeguin.

addons/mail/models/mail_blacklist.py

@@ -59,15 +59,17 @@ def write(self, values):
         return super(MailBlackList, self).write(values)
 
     def _add(self, email):
-        record = self.env["mail.blacklist"].with_context(active_test=False).search([('email', '=', email)])
+        sanitized = self._sanitize_email(email)
+        record = self.env["mail.blacklist"].with_context(active_test=False).search([('email', '=', sanitized)])
         if len(record) > 0:
             record.write({'active': True})
         else:
             record = self.create({'email': email})
         return record
 
     def _remove(self, email):
-        record = self.env["mail.blacklist"].with_context(active_test=False).search([('email', '=', email)])
+        sanitized = self._sanitize_email(email)
+        record = self.env["mail.blacklist"].with_context(active_test=False).search([('email', '=', sanitized)])
         if len(record) > 0:
             record.write({'active': False})
         else: