Make interface_choice option effective (#35444)

I missed the second commit that actually makes this
work in the original merge.

homeassistant/components/zeroconf/__init__.py

@@ -56,7 +56,7 @@ CONFIG_SCHEMA = vol.Schema(
 
 def setup(hass, config):
     """Set up Zeroconf and make Home Assistant discoverable."""
-    if config.get(CONF_DEFAULT_INTERFACE):
+    if DOMAIN in config and config[DOMAIN].get(CONF_DEFAULT_INTERFACE):
         zeroconf = Zeroconf(interfaces=InterfaceChoice.Default)
     else:
         zeroconf = Zeroconf()

tests/components/zeroconf/test_init.py

@@ -92,6 +92,19 @@ async def test_setup_with_default_interface(hass, mock_zeroconf):
     assert mock_zeroconf.called_with(interface_choice=InterfaceChoice.Default)
 
 
+async def test_setup_without_default_interface(hass, mock_zeroconf):
+    """Test without default interface config."""
+    with patch.object(hass.config_entries.flow, "async_init"), patch.object(
+        zeroconf, "ServiceBrowser", side_effect=service_update_mock
+    ):
+        mock_zeroconf.get_service_info.side_effect = get_service_info_mock
+        assert await async_setup_component(
+            hass, zeroconf.DOMAIN, {zeroconf.DOMAIN: {CONF_DEFAULT_INTERFACE: False}}
+        )
+
+    assert mock_zeroconf.called_with()
+
+
 async def test_homekit_match_partial_space(hass, mock_zeroconf):
     """Test configured options for a device are loaded via config entry."""
     with patch.dict(