Move london_air fixture to integration test (#112991)

* Move london_air fixture to integration test

* Fix

tests/components/london_air/test_sensor.py

@@ -18,7 +18,9 @@ async def test_valid_state(
 ) -> None:
     """Test for operational london_air sensor with proper attributes."""
     requests_mock.get(
-        URL, text=load_fixture("london_air.json"), status_code=HTTPStatus.OK
+        URL,
+        text=load_fixture("london_air.json", "london_air"),
+        status_code=HTTPStatus.OK,
     )
     assert await async_setup_component(hass, "sensor", VALID_CONFIG)
     await hass.async_block_till_done()