test: fix settings-mock leak that failed SESSION_MAX_AGE_SECONDS tests in CI

The shared mock_settings fixture replaced settings with a MagicMock lacking
SESSION_MAX_AGE_SECONDS, so create_app()'s SessionMiddleware wiring and the
session-max-age assertions saw a MagicMock instead of an int under certain test
orderings (green locally with tests/integration ignored, red in full CI). Give the
mock a real SESSION_MAX_AGE_SECONDS (28800) so numeric reads/comparisons hold.

Full CI unit suite now passes locally: 4076 passed.

Author: test

operations-manager/python/tests/conftest.py

@@ -119,6 +119,9 @@ def mock_settings() -> Any:
         mock_settings.KEYCLOAK_URL = ""
         mock_settings.PROMETHEUS_EXTERNAL_URL = ""
         mock_settings.PROMETHEUS_URL = ""
+        # Real int, not a bare MagicMock: create_app() reads this to wire SessionMiddleware,
+        # and numeric comparisons on it must work even when this mock is in effect.
+        mock_settings.SESSION_MAX_AGE_SECONDS = 28800
         yield mock_settings