[FIX] lunch: remove freezetime class decorator

Using freezetime to decorate a TestCase can have strange effects.

It looks like an override but monkeypatching the
setUpClass/tearDownClass. It started breaking between python 3.10.6 and
3.10.12. See pr message for more details.

closes odoo/odoo#137215

Signed-off-by: Christophe Monniez (moc) <moc@odoo.com>

addons/lunch/tests/common.py

@@ -5,14 +5,12 @@ from freezegun import freeze_time
 from odoo.tests import common, new_test_user
 
 
-fakenow = datetime(2021, 1, 29, 12, 20, 0)
-
-@freeze_time(fakenow)
 class TestsCommon(common.TransactionCase):
     @classmethod
     def setUpClass(cls):
         super().setUpClass()
-        cls.fakenow = fakenow
+        cls.fakenow = datetime(2021, 1, 29, 12, 20, 0)
+        cls.startClassPatcher(freeze_time(cls.fakenow))
 
     def setUp(self):
         super(TestsCommon, self).setUp()