community/pipewire: make -pulse provide PulseAudio
This way it can be used as a full PulseAudio replacement, which you want anyway when you install this package.
This also makes sure the provides_priority of PulseAudio is at least higher than pipewire-pulse, so any package requiring PulseAudio will pull in PulseAudio by default rather than pipewire-pulse.
CC @maribu