Translation Demo not working, text doesn't translate (4.0-dev)

[voylin]

Which demo project is affected:
https://github.com/godotengine/godot-demo-projects/tree/4.0-dev/gui/translation

OS/device including version:
Arch linux lts-5.15.31-1 With i3 Window manager

Issue description:
The demo does not translate sound, does not change flag and does not play any other audio than the English audio.

[aaronfranke]

Fixed by #704 for Godot 4.0.