Handle race condition in harmony setup (#33611)

* Handle race condition in harmony setup

If the remote was discovered via ssdp before the yaml config import
happened, the unique id would already be set and the import
would abort.

* Update homeassistant/components/harmony/config_flow.py

Co-Authored-By: Paulus Schoutsen <paulus@home-assistant.io>

* reduce

* black

Co-authored-by: Paulus Schoutsen <paulus@home-assistant.io>