Fix C# file extension not appearing in Search in File Extensions default

[Calinou]

I'm not sure if this is a proper fix, but it seems the code path isn't being triggered correctly according to the proposal.

This closes godotengine/godot-proposals#2766.

[neikeq]

Last time I checked MODULE_*_ENABLED are only defined inside modules/ sources, did this change?
I'm wondering why the GodotSharp singleton isn't present though as we register it here:

godot/modules/mono/register_types.cpp

Line 49 in 9990f28

Engine::get_singleton()->add_singleton(Engine::Singleton("GodotSharp", _GodotSharp::get_singleton()));

Is the ProjectSettings constructor being called before register_module_types?

[mysliwy112]

As far as I tested using Engine.HasSingleton("GodotSharp") in C# returns True when running game through Godot Mono.

[neikeq]

So apparently ProjectSettings constructor is called before register_module_types, so that explain why the singleton is not present yet.

[AThousandShips]

Is this still relevant? Several changes have been made since this, most recently:

• Replace .NET detection code with ClassDB::class_exists("CSharpScript"). #94680