wayland: consider every commit a "content update" for presentation time

The protocol doesn't have a definition of what it means, but damage is a flawed interpretation. Color management changes are arguably content updates, so are viewporter changes, so are blur changes and so on.

Also see https://gitlab.freedesktop.org/wayland/wayland-protocols/-/issues/36 for an upstream discussion of this

(cherry picked from commit d5ca4296)