Replace the local package derivation with the one now provided by the
vhost-device flake, removing packages/vhost-device-sound.nix.
Also bump wayland-proxy-virtwl.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
We're already starting a dbus normally, the wrapped dbus-launch is
not needed. Passing a command also prevents sommelier from working.
Also update sommelier since the old version was broken for virtio-gpu.
