extensionPrefs: Request correct GDK/GTK versions
gjs no longer has an implicit dependency on GTK 3.0, so without requesting an explicit version, we will get the highest available.
Our code isn't GTK-4 ready, so request 3.0 explicitly.
gjs no longer has an implicit dependency on GTK 3.0, so without requesting an explicit version, we will get the highest available.
Our code isn't GTK-4 ready, so request 3.0 explicitly.