Import default for Remove Immutable Tracks ignored

### Tested versions

- Reproducible in Windows / 4.4.1 stable, as well as 4.3

### System information

Godot v4.4.1.stable - Windows 11 (build 26100) - Multi-window, 1 monitor - Vulkan (Forward+) - dedicated NVIDIA GeForce RTX 4090 (NVIDIA; 32.0.15.7652) - AMD Ryzen 9 7950X3D 16-Core Processor (32 threads)

### Issue description

Turning off Project Settings > Import Defaults > Remove Immutable Tracks should cause newly imported .glb (at least, have not tried other formats) animations to have the Remove Immutable Tracks option turned off, however the Remove Immutable Tracks in newly imported animation is still on, regardless of this setting, and needs to be turned off manually.

(The reason for wanting it off is that it messes up quite a lot of animations)

### Steps to reproduce

- Set Project Settings > Import Defaults > Remove Immutable Tracks to off
- Copy over a .glb animation file somewhere in the project
- The file will be picked up and imported
- Double click the .glb file, and look at the Remove Immutable Tracks flag
- Expectation is it should be off, according to the import default set earlier. It is however on, and needs to be turned off manually

### Minimal reproduction project (MRP)

N/A