gtk: Upgrade 4.12.1 -> 4.12.3

gtk: Upgrade 4.12.1 -> 4.12.3

Overview of Changes in 4.12.3, 28-09-2023
=========================================

* GtkWindow:
 - Don't assume titlebars are GtkHeaderBar

* GtkTreeView:
 - Fix a crash in gtk_tree_view_is_blank_at_pos

* printing:
 - Fix some issues with the portal implementation

* GSK:
 - Some optimizations in the GL renderer
 - Fix memory leaks in the Broadway renderer

* demos:
 - Fix a crash in gtk4-demo

* Translation updates
 Basque
 Brazilian Portuguese
 Czech
 Galician
 Georgian
 German
 Hungarian
 Kazakh
 Lithuanian
 Persian
 Polish
 Spanish
 Swedish
 Turkish

Overview of Changes in 4.12.2, 20-09-2023
=========================================

* GtkTooltip:
 - Don't cross native boundaries when looking for tooltips

* GtkCenterLayout, GtkEntry, GtkSearchEntry:
 - Fix some issues with baseline handling

* GtkSwitch:
 - Respect text direction

* Theme:
 - Use relative font sizes

* GSK:
 - Make repeated gradients match between GL and cairo
 - Make rounded rect shrinking match between Vulkan, GL and cairo
 - Fix parsing of text nodes with color glyphs
 - Restrict an optimization to the cases where it is correct
 - Fix rendering of shadows with opacity

* macOS:
 - Clamp damage regions to the surface size

* Windows:
 - Fix missing minimize and maximize buttons

* Translation updates
 Basque
 Brazilian Portuguese
 Catalan
 Chinese (China)
 Czech
 Danish
 Dutch
 Finnish
 Galician
 German
 Hungarian
 Italian
 Kazakh
 Latvian
 Lithuanian
 Slovenian
 Spanish
 Turkish

Signed-off-by: Markus Volk <f_l_k@t-online.de>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>