Fix MODEL_NORMAL_MATRIX in fragment function of spatial shader

[Chaosus]

No description provided.

[clayjohn]

This makes me realize that we need to re-evaluate what we are doing with the regular model matrix. Both the model matrix and the model_normal_matrix get adjusted by the multimesh transform (when uses multimeshes) But in the fragment shader the extra transform is not applied so the model_matrix won't match in the fragment and the vertex shaders.

[Chaosus]

@clayjohn Should I change something in this PR?

[clayjohn]

@clayjohn Should I change something in this PR?

Not yet no. We need to discuss what we want to do with the regular matrix as right now the model_matrix will be different between the vertex shader and the fragment shader right now which is not good.

[jsjtxietian]

Should we delete the fragement MODEL_NORMAL_MATRIX part in documentaion for now ? Users will get confused : #85586

[Chaosus]

I've lost my thoughts about this PR, so I'll close it.