policy-node: wait for nodes when we become unlinked

If we were linked before but our node is removed, wait until a new node
becomes available instead of failing.

This fixes an issue where there is only 1 sink available and the card
profile is toggeled between pro and stereo. After the profile is
toggled, the sink is removed and the node would be killed with an error
because there is no fallback sink. The fix is similar to the
pipewire-media-session logic.
7 jobs for wait-reconnect in 3 minutes and 51 seconds (queued for 25 seconds)
Status Name Job ID Coverage
  Container
passed container_fedora #15962925

00:00:25

passed container_ubuntu #15962926

00:00:16

 
  Build
passed build_on_fedora_no_docs #15962928

00:00:54

passed build_on_fedora_with_docs #15962927

00:02:26

passed build_on_ubuntu_no_gir #15962930

00:00:47

passed build_on_ubuntu_with_gir #15962929

00:01:49

 
  Analysis
passed shellcheck #15962931

00:00:23