Fbx2Gltf produces malformed gltf file

### Godot version

FBX2glTF v0.13.1

### System information

Windows 11

### Issue description

Fbx2Gltf produces malformed gltf (glb) file that doesn't pass validation:

```
{
"code": "EMPTY_ENTITY",
"message": "Entity cannot be empty.",
"severity": 0,
"pointer": "/animations/0/channels"
},
{
"code": "EMPTY_ENTITY",
"message": "Entity cannot be empty.",
"severity": 0,
"pointer": "/animations/0/samplers"
},
```

[UncappedCilinderWithRotatedUVProjection.zip](https://github.com/user-attachments/files/23485418/UncappedCilinderWithRotatedUVProjection.zip)

### Steps to reproduce

Run the tool on attached fbx file and run the output through validator https://github.khronos.org/glTF-Validator/

### Minimal reproduction project

-

Reproduce the issue with the attached UncappedCilinderWithRotatedUVProjection.fbx using FBX2glTF v0.13.1, then run the generated glb through the Khronos glTF Validator. Trace the conversion path responsible for the empty animation channels and samplers, and consider the issue done when the output no longer reports these validation errors.

Written by the indexing model from the issue text.