Downgrade 'Unable to find purge backend' messages to info (#11899)

wagtail/contrib/frontend_cache/tests.py

@@ -485,7 +485,7 @@ class TestCachePurgingFunctions(TestCase):
         }
     )
     def test_invalidate_specific_location(self):
-        with self.assertLogs(level="WARNING") as log_output:
+        with self.assertLogs(level="INFO") as log_output:
             purge_url_from_cache("http://localhost/foo")
 
         self.assertEqual(PURGED_URLS, [])

wagtail/contrib/frontend_cache/utils.py

@@ -116,7 +116,7 @@ def purge_urls_from_cache(urls, backend_settings=None, backends=None):
         }
 
         if not backends_for_hostname:
-            logger.warning("Unable to find purge backend for %s", hostname)
+            logger.info("Unable to find purge backend for %s", hostname)
             continue
 
         for backend_name, backend in backends_for_hostname.items():