Drop asynctest (#44746)

tests/components/shell_command/test_init.py

@@ -3,12 +3,11 @@
 import os
 import tempfile
 from typing import Tuple
+from unittest.mock import MagicMock, patch
 
 from homeassistant.components import shell_command
 from homeassistant.setup import async_setup_component
 
-from tests.async_mock import MagicMock, patch
-
 
 def mock_process_creator(error: bool = False):
     """Mock a coroutine that creates a process when yielded."""