Error spam when re-importing a model with a saved `SkeletonProfile`, and model breakage when deleting a resource

[JekSun97]

Tested versions

4.4 dev6

System information

Godot v4.4.dev6 - Windows 10.0.19045 - Multi-window, 1 monitor - Vulkan (Forward+) - dedicated Radeon RX 560 Series (Advanced Micro Devices, Inc.; 31.0.14001.45012) - Intel(R) Core(TM) i5-4570 CPU @ 3.20GHz (4 threads)

Issue description

If we save the SkeletonProfileHumanoid resource in the model import window, then click the re-import button, a spam of errors occurs. Also, if we delete a previously saved resource and try to open the model in the model import window, it will break and will not open.

Steps to reproduce

1. Open the Shibahu_skechfab.fbx model import window
2. Create a new BoneMap
3. Create a new SkeletonProfileHumanoid and save it as a resource
4. Click the Retry Import button
5. A huge number of errors (You can also clear the BoneMap and see the errors again)
6. Delete your previously saved SkeletonProfileHumanoid resource and the model breaks and will not open again (Reload the project to make sure).

Minimal reproduction project (MRP)

The manipulations were carried out with the model from this comment: https://github.com/godotengine/godot/pull/99999#pullrequestreview-2477151374 Model: https://sketchfab.com/3d-models/shibahu-2e9dffd948f747668609a5a477daad86

[JekSun97]

I hope that someone will fix this problem before the release of 4.4, because it is quite critical, now my model broke again when I wanted to reassign SkeletonProfileHumanoid only in 4.3, so we can say that it is also in 4.3 stable.