test(django): Run user identity ASGI test in a forked process

The new test was the only DB-touching test without @pytest.mark.forked. Running in the parent process leaked the created user into the shared in-memory sqlite DB (UNIQUE constraint failures in test_basic) and caused the parent to hold the session-scoped django_db_setup fixture, so forked children skipped postgres test DB creation but still destroyed it on teardown (database does not exist errors).

Author: ericapisani

tests/integrations/django/asgi/test_asgi.py

@@ -1102,6 +1102,7 @@ async def test_async_middleware_process_exception_is_awaited(
     assert response["body"] == b"handled by async process_exception"
 
 
+@pytest.mark.forked
 @pytest.mark.parametrize("application", APPS)
 @pytest.mark.asyncio
 @pytest.mark.skipif(