GLTF importer does not read the "matrix" property for nodes

[karai17]

Godot version

4.1.2

System information

Godot 4.1.2

Issue description

I am generating valid GLTF files from raw model data. The Node transforms in my data come in mat4 format so I have been using the node.matrix property to dump that data in. My GLTF file loads perfectly fine in Blender, but does not load properly in Godot. After many, many hours of tinkering, of which I will spare the details, the primary issue ended up being that Godot just doesn't read the matrix property and I had to decompose my matrix into the TRS values. I suspect this omission is due to Blender spitting out GLTF files with TRS properties and never the matrix property, and an assumption that Godot users will primarily be using Blender.

Steps to reproduce

1. Generate or modify a valid GLTF file such that the nodes use the matrix property rather than the TRS properties
2. Import model into Godot
3. Model should now have a very strange structure presumably from default TRS values being used rather than the provided matrix

Minimal reproduction project

TRS model (expected behaviour)
buma.zip

Matrix model (unexpected behaviour)
buma (2).zip

Ignore the orientation of the model~

[aaronfranke]

This seems to be specifically a problem with skeletons. And the current code is bogus:

			skeleton->set_bone_rest(bone_index, node->xform);
			skeleton->set_bone_pose_position(bone_index, node->position);
			skeleton->set_bone_pose_rotation(bone_index, node->rotation.normalized());
			skeleton->set_bone_pose_scale(bone_index, node->scale);

There is no reason where we would ever have separate values for these. In fact, they should be unified, with GLTFNode only storing one transform.