pulseaudio: enable glib schema installation

[zdykstra]

General

• This is a new package and it conforms to the quality requirements

Have the results of the proposed changes been tested?

• I use the packages affected by the proposed changes on a regular basis and confirm this PR works for me
• I generally don't use the affected packages but briefly tested this PR

paprefs relies on org.freedesktop.pulseaudio.gschema.xml being installed / compiled into /usr/share/glib-2.0/schemas/ .

(paprefs:8700): GLib-GIO-ERROR **: 13:13:47.730: Settings schema 'org.freedesktop.pulseaudio.module-group' is not installed
fish: Job 1, 'paprefs' terminated by signal SIGTRAP (Trace or breakpoint trap)