glTF export does not apply uv1_* and uv2_* properties

### Tested versions

Tested in v4.6.rc2.mono.official [78c6632eb]

### System information

Godot v4.6.rc2.mono - Windows 10 (build 19045) - Multi-window, 3 monitors - Vulkan (Forward+) - dedicated NVIDIA GeForce GTX 1070 Ti (NVIDIA; 32.0.15.8157) - AMD Ryzen 5 5600X 6-Core Processor (12 threads) - 31.92 GiB memory

### Issue description

`uv1_scale` `uv1_offset` `uv1_triplanar` and the corresponding `uv2_` props do not apply to the exported glTF file.

### Steps to reproduce

Change the `uv1_offset` of a material then export it by doing Scene -> Export As... -> glTF 2.0 Scene.
Open the exported glTF file, the offset will be incorrect.

### Minimal reproduction project (MRP)

N/A

Start by reproducing the issue through Scene → Export As... → glTF 2.0 Scene after changing a material's uv1_offset. Trace the glTF export path to determine where uv1_* and uv2_* properties are handled; done means the exported glTF preserves those property values.

Written by the indexing model from the issue text.