community/gnome-shell: pulls in wireplumber through gst-plugin-pipewire

The gnome-shell pulls in wireplumber through gst-plugin-pipewire, which breaks PulseAudio.

gst-plugin-pipewire was initially added to dependencies in commit da6c87f1, as it's required for the built-in screen recording functionality, which fails silently without it. cc @team/gnome - what should we do in this case? Add some kind of subpackage to the gnome package to install it only if pipewire is installed, or just drop it entirely?