Cleanup mqtt PLATFORMS constant and CI-test platform filters (#112847)

tests/components/mqtt/test_light_json.py

@@ -96,7 +96,6 @@ from homeassistant.const import (
     STATE_OFF,
     STATE_ON,
     STATE_UNKNOWN,
-    Platform,
 )
 from homeassistant.core import HomeAssistant, State
 from homeassistant.helpers.json import json_dumps
@@ -170,13 +169,6 @@ COLOR_MODES_CONFIG = {
 }
 
 
-@pytest.fixture(autouse=True)
-def light_platform_only():
-    """Only setup the light platform to speed up tests."""
-    with patch("homeassistant.components.mqtt.PLATFORMS", [Platform.LIGHT]):
-        yield
-
-
 class JsonValidator:
     """Helper to compare JSON."""