CPAL 0.18 dev branch won't pick the PipeWire backend within Snap, even with the :pipewire interface manually connected

It will fallback on the ALSA or PulseAudio backend instead, while an unsandboxed application will pick PipeWire, and a Flatpak package with the `--filesystem=xdg-run/pipewire-0` flag will pick PipeWire too. Also it doesn't seem to use the PipeWire XDG portal which isn't optimal. Tested on: Ubuntu 26.04 Tested with: CPAL 0.18 latest development commit - abc0cc2 - options `pipewire` and `pulseaudio` manually enabled Tested using: `pavucontrol` in the Recording tab to check whether the test application uses ALSA, PipeWire or PulseAudio as a backend Tested with test application (inside Snap): https://snapcraft.io/songrec, `edge` branch See for reference: https://snapcraft.io/docs/reference/interfaces/pipewire-interface/ The Snap PipeWire interface can be connected using `sudo snap connect songrec:pipewire`, but it seems to do effectively nothing here.