Fix patching for DNS queries in Obihai (#166790)

tests/components/obihai/test_config_flow.py

@@ -144,7 +144,10 @@ async def test_dhcp_flow_auth_failure(hass: HomeAssistant) -> None:
             == DHCP_SERVICE_INFO.ip
         )
 
-    # patch_gethostbyname fixture is active
+    with (
+        patch("homeassistant.components.obihai.config_flow.gethostbyname"),
+    ):
+        # Verify we get dropped into the normal user flow with non-default credentials
         result = await hass.config_entries.flow.async_configure(
             result["flow_id"],
             user_input={