it is safe to remove libcanberra-gstreamer and lib32-libcanberra-gstreamer. you can do so with the following:
sudo pacman -Rdd libcanberra-gstreamer lib32-libcanberra-gstreamer
WARNING: removing this orphans lib32-gstreamer. i believe this is a bug, because removing this package and it’s dependencies results in an unbootable system.
EDIT: I may have spoken too soon - i do indeed have a system that is failing to boot after update, but it appears to be due to a separate issue. After I fixed that, I was able to remove lib32-gstreamer (and it’s dependencies) without issue. Apologies for the false alarm. I can confirm this is safe to remove.