Skeleton Path is not assigned correctly when importing a glb with bound MeshInstance as a child of BoneAttachment

### Tested versions

v4.3.stable.mono.official [77dcf97d8]
v4.4.dev3.mono.official [f4af8201b]

### System information

Godot v4.3.stable.mono - Windows 10.0.22631 - Vulkan (Forward+) - dedicated NVIDIA GeForce RTX 4080 (NVIDIA; 32.0.15.5599) - AMD Ryzen 9 7950X3D 16-Core Processor (32 Threads)

### Issue description

In Godot 4.3 my imported model is distorted when running the game. I have a model imported as GLB from Blender and added to a 3d scene. I also added a camera. In editor everything looks fine:


Also the camera preview looks fine.


But when I run the game, the model is distorted, e.g. the body gets scaled up a lot while the hands and eyes move but retain their scale.


This same scene works just fine in Godot 4.2.


### Steps to reproduce

Open the MRP in both Godot 4.2 and Godot 4.3, run the `node_3d.tscn` scene to see the results.

### Minimal reproduction project (MRP)

[bone_problem_reproducer.zip](https://github.com/user-attachments/files/17265753/bone_problem_reproducer.zip)

Open bone_problem_reproducer.zip in Godot 4.2 and 4.3, then run node_3d.tscn to reproduce and compare the model distortion. Trace the GLB import case involving a bound MeshInstance under BoneAttachment and verify how its Skeleton Path is assigned. Done means the scene runs without distortion in the affected version, matching the 4.2 result.

Written by the indexing model from the issue text.