[IMP] website: avoid query on website table when serving empty page

Getting the `res.company` record by browsing the `company_id` cached
value from `website` instead of reading it directly on the website
record will avoid a read on the website table.

While this might seems unusual and not elegant, since this is a very
low level method used to render every view, it seems fine.

task-2774979

X-original-commit: bc643a573a7339c82661cbcff2cc59bdd0eec3e3
Part-of: odoo/odoo#85456

addons/website/tests/test_performance.py

@@ -116,7 +116,7 @@ class TestWebsitePerformance(UtilPerf):
         # website.page with no call to layout templates
         self.page.arch = '<div>I am a blank page</div>'
         self.assertEqual(self._get_url_hot_query(self.page.url), 5)
-        self.assertEqual(self._get_url_hot_query(self.page.url, cache=False), 6)
+        self.assertEqual(self._get_url_hot_query(self.page.url, cache=False), 5)
 
     def test_40_perf_sql_queries_page_multi_level_menu(self):
         # menu structure should not impact SQL requests