x11-wm/picom: Update 12.2 → 12.3

Changelog:
Improvements

• Extend workaround for missing hardware accelerated convolution to more drivers Bug fixes
• Fix memory corruption that can happen when handling window property changes
• Fix force-win-blend having no effect
• Fix shadow being rendered incorrectly in xrender backend

https://github.com/yshui/picom/releases/tag/v12.3

PR: 282083
MFH: 2024Q4
(cherry picked from commit f7461335b3052cab4d94cc521b952e401c3454f4)