Connection between pw-record and mic not shown until the view is refreshed

This was seen in qpwgraph built from main branch with qt6, latest pipewire with wireplumber session manager.

How to reproduce:

1. pw-record /tmp/pappo.wav
2. check connections in qjackctl, pw-record and sound card capture port are connected
3. run qpwgraph, pw-record and sound card capture port appear to be not connected

In addition, creating/destroying any other connection makes the above connection suddenly appear. This also happens for connections created automatically by the session manager, so probably anything that triggers a refresh of the graph makes it appear.