Enable changing editor language without restart

[KoBeWi]

Currently changing editor language requires editor restart. Godot has a good auto-translation system, which is under-utilized in the editor. For a long time the editor auto-translation was completely disabled. Then there is TTR method which we use everywhere, which makes it impossible to auto-translate, because it immediately translates the string.

#75012 enabled auto-translation to work in the editor, and recently there were some efforts to replace TTR with TTRC (e.g. #99158). Also in 4.4 there were various GUI enhancements that added better localization support to many Control nodes.

This PR makes another step - it actually enables language switching in the editor.

godot.windows.editor.dev.x86_64_U2VP5Pd26j.mp4

Though as you can see, it's very basic right now. For proper language switching we need to use TTRC where possible, and NOTIFICATION_TRANSLATION_CHANGED where not (e.g. in format strings). Thus, while the PR makes changing the language setting have immediate effect, the user is still prompted to restart the editor as before.

IMO enabling this before the editor is ready is harmless, while it allows for easier testing of auto-translation. Eventually we will be able to properly switch editor language without restart at all.

Included some extra changes to the top menu bar, to make it more obvious that the language has changed.

[timothyqiu]

Perhaps we should also remove this editor hint check in SceneTree. So that NOTIFICATION_TRANSLATION_CHANGED can propagate.

godot/scene/main/scene_tree.cpp

Lines 772 to 775 in cae3d72

	case NOTIFICATION_TRANSLATION_CHANGED: {
	if (!Engine::get_singleton()->is_editor_hint()) {
	get_root()->propagate_notification(p_notification);
	}

[KoBeWi]

Removed.
I don't know how it worked before, removing check was required for the switch to actually take effect. Maybe I reverted it by accident before pushing, idk.

[Repiteo]

Thanks!

[arkology]

@KoBeWi after changing, for example, "en"->"ar"->"en", editor will keep right-to-left direction.
Issue - #104690

[bruvzg]

Most likely some of the direction dependent editor icons aren't reloaded when direction changes, I'll check it later.