magnifier: Use the new get_client_content_rect API
As we have removed is_client_decorated from Mutter in the last release. Instead of re-adding it and re-exposing SSD/CSD differences and making gnome-shell deal with that, we created a new API that does exactly what is_client_decorated was used for, so switch to using that.
Fixes #7984 (closed)
Needs mutter!4087 (merged)
Edited by Bilal Elmoussaoui