Use new style for built-in ws commmands (#21694)

* Use new style for built-in ws commmands

* Lint

tests/components/websocket_api/test_init.py

@@ -5,7 +5,7 @@ from unittest.mock import patch, Mock
 from aiohttp import WSMsgType
 import pytest
 
-from homeassistant.components.websocket_api import const, commands, messages
+from homeassistant.components.websocket_api import const, messages
 
 
 @pytest.fixture
@@ -56,7 +56,7 @@ def test_pending_msg_overflow(hass, mock_low_queue, websocket_client):
     for idx in range(10):
         yield from websocket_client.send_json({
             'id': idx + 1,
-            'type': commands.TYPE_PING,
+            'type': 'ping',
         })
     msg = yield from websocket_client.receive()
     assert msg.type == WSMsgType.close