Not ideal behavior if any asset data is not found in the filesystem

[endersaka]

Describe the bug
I installed MPFB for the first time and loaded the makehuman_system_assets from an old ZIP, I already had backup locally (now I can say that it was probably outdated). Once ready, I tried to load the eyes onto a character and I got the typical Blender text box alert with a Python stack trace, the eyes were loaded without textures, outside of the rig hierarchy and in a location far away from the model. The Python panel, showed an error, clearly telling me that the script wasn't able to load the eyes materia, since the material folder was missing.
I resolved the issue by downloading and updating the assets pack, though such behavior is not ideal. The script should handle the error and present to the user a more user-friendly error and eventually load the eyes correctly even if without the material.

Checklist

• If you are using blender 4, did you use the blender 4 specific build?
  I don't understand what you mean.

• If you recently upgraded mpfb2, did you read http://static.makehumancommunity.org/mpfb/faq/ensure_correct_version.html
  No, I didn't read it but the Blender Extension page of MPFB states that Blender 4.2.1 LTS is the minimum version, which is exactly what I have (also, I sincerely hope that Blender developers have figured out a method to prevent installation of not compatible extension versions).

Screenshots / logs
I can't give you much more information. As you know the Python stack trace error panel in Blender is copy and paste resistant :-) and disappears without leaving a log anywhere (as far as I know).

Platform and versions

• OS: Windows?
• Version of Blender: 4.2.1 LTS
• Version of MPFB: it's 2.0.12, according to Add-ons information panel in the Blender preferences.