community/gtk4.0: upgrade to 4.12.4

https://gitlab.gnome.org/GNOME/gtk/-/compare/4.12.3...4.12.4 -> code changes lgtm

Changelog

Overview of Changes in 4.12.4, 17-11-2023
=========================================

* a11y:
 - Tweak name computation for some corner cases

* gdk:
 - gl: Improve our use of GLES a bit (use vertex arrays and
   GL_BGRA if available)
 - Fix some errors in our memory format tables

* gsk:
 - gl: handle texture-scale nodes more faithfully
 - gl: Fix icon padding in the atlas

* Windows:
 - Stop relying on glib for build configuration

* Tools:
 - Add a --undecorated option to gtk4-rendernode-tool

* Translation updates
 Catalan
 French
 Romanian
 Russian
 Spanish
 Turkish

https://gitlab.gnome.org/GNOME/gtk/-/blob/0cdb58af49aac6061cce81ffee75e11baf100cf9/NEWS