[FIX] account_financial_report: Fix tests

On multi-company settings, we need to make sure we are searching and creating objects with the correct company associated.
Also take into account previously created account groups

 TT28423

account_financial_report/tests/test_open_items.py

@@ -7,6 +7,7 @@ from odoo.tests.common import TransactionCase
 
 class TestOpenItems(TransactionCase):
     def test_partner_filter(self):
+        self.env.user.company_id = self.env.ref("base.main_company").id
         partner_1 = self.env.ref("base.res_partner_1")
         partner_2 = self.env.ref("base.res_partner_2")
         partner_3 = self.env.ref("base.res_partner_3")