ci: ensure timestamp is up to date for heartbeat test

tests/test_device.py

@@ -604,6 +604,7 @@ async def test_async_receive(subject, mock_api, mocker):
     mock_api().set_socketPersistent.reset_mock()
     mock_api().status.reset_mock()
     # Wait long enough to force a heartbeat poll on the next iteration
+    subject._cached_state = subject._cached_state | {"updated_at": time()}
     await asyncio.sleep(10.1)
     # Call the function under test
     print("getting second iteration...")