main/postmarketos-base-ui: drop pulseaudio wireplumber config
This was upstreamed to Alpine aports, see aports@cc2f22db473
Fixes:
(452/643) Installing postmarketos-base-ui-audio-pulseaudio (24-r0)
ERROR: postmarketos-base-ui-audio-pulseaudio-24-r0: trying to overwrite usr/share/wireplumber/wireplumber.conf.d/50-pulseaudio.conf owned by pulseaudio-wireplumber-17.0-r1.