editors/vim: Pull in gnome.mk's gdkpixhufextra to fix runtime warnings

Non-fatal console warnings were generated when running vim-gtk3 and 2.
This is due to certain loadable modules moving from gdk-pixhuf to
gdk-pixbuf-extras.

See https://forums.freebsd.org/threads/gvim-messages-gdkpixbuf-warning-and-glib-gobject-critical.98679/
PR: Yusuf Yaman
Reported by: thierry, in the above FreeBSD Forums post
MFH: 2025Q3

(cherry picked from commit 4ff220b80cf4286245553213313790f14d3220a2)