get_collision_face_index() is not implemented

[maylokana]

Describe the bug

RayCast3D's get_collision_face_index() doesn't work at all I tested this with the .NET build and originally stumbled across it with C# scripts, but it seems to be non-functional with GDScript as well. Code works perfectly fine with in-built physics

To Reproduce

1. Create a StaticBody3D attached with a ConcavePolygonShape3D
2. Create a RayCast3D
3. Use the raycast's get_collision_face_index() function

Expected behavior

Please don't make me say "get_collision_face_index() didn't work" because I'm going to say that it did this and always returned -1

Environment:

• OS: Windows 10 22H2
• Version v0.8.5
• Godot Version: 4.3.stable.mono
• Type 3d-single-enchanced-determinism

Example project(zip)

Written in GDScript to test non-mono builds raytouchy-example.zip