webkitgtk,wpewebkit: bump to version 2.34.3

[psaavedra]

This is a bug fix release in the stable 2.34 series.

Release notes:

• Make audio tools (like mixers) display the actual name of the application producing sound, instead of a generic one.
• Fix several crashes and rendering issues.

Ref:

• https://webkitgtk.org/2021/12/20/webkitgtk2.34.3-released.html
• https://wpewebkit.org/release/wpewebkit-2.34.3.html