settings: Replace canberra-gtk by to gsound
Mainly to reduce the number of GTK3 dependencies before actually start porting the library. Fortunately, the usage of libcanberra-gtk by gnome-bluetooth is rather trivial, so porting to gsound is just a few lines of code away.
Replace canberra-gtk by gsound, adjust the build system to reflect that, and update the CI file to install gsound-devel instead of libcanberra-devel.