GTK3: Updated Gtk3 units generated with new gir2pas version.

This change fixes translation of enums and bit fields after recent fin in gir2pas tool.

This required a code change in gtk3cobject.inc as some bit fields were treated as enums while they are now treated as sets.

Units were generated using the following command on Debian Bookworm (12)

gir2pas -P Laz -e Set -i /usr/share/gir-1.0/Gtk-3.0.gir -o gtk3bindings

Then, some functions were removed manually to enable support of Debian Bullseye (11.6).