OBJ file format do not load default material

[JulianKnodt]

Is your feature request related to a problem? Please describe.
When loading an OBJ file, an empty default material is always added. This material isn't necessary.

Describe the solution you'd like
Only add a default material if no other materials are added (or do not add any material)

Describe alternatives you've considered
I can ignore the default material, but it is strange that it is there in the first place when other materials are present.

Additional context
Add any other context or screenshots about the feature request here.