Refactor zeroconf setup to be async (#39955)

* Refactor zeroconf setup to be async

Most of the setup was calling back to async because
we were setting up listeners.  Since we only need
to jump into the executor to create the zeroconf
instance, its much faster to setup in async.

In testing this cut the setup time in half
or better.

* partial revert to after_deps

tests/components/zeroconf/conftest.py

@@ -1,11 +0,0 @@
-"""conftest for zeroconf."""
-import pytest
-
-from tests.async_mock import patch
-
-
-@pytest.fixture
-def mock_zeroconf():
-    """Mock zeroconf."""
-    with patch("homeassistant.components.zeroconf.HaZeroconf") as mock_zc:
-        yield mock_zc.return_value