With pipewire, card ports are added or removed after the card is visible to us.
This is intended from the pipewire side, as audio routing is dynamic and can
change at any time.

This is the case for Bluetooth devices, where there are multiple ports for
the different profiles available. In case a profile becomes available or
goes unavailable (likely this can happen on connection issues on the Bluetooth
link), the ports will change.

Support this scenario by updating the ports list on card changes, adding new
ports (and creating new respective ui-devices) and removing ports (and removing
the respective ui-devices).

Now that we can add ports after creating the card, this likely means we can
remove handling for portless cards. At least Bluetooth devices nowadays have
ports, but they get them later.