deskutils/xfce4-notifyd: Correctly depend on canberra for sound support

Upstream configure script does not have a specific canberra knob,
so use the sound knob to really control linking to canberra library
for sound support.

To better describe the option I renamed it to SOUND (still disabled
by default)

PR:		273805
Fixes:		4018c202
MFH:		2023Q3