Material has duplicated flags

[Nielsbishere]

Is your request related to a problem? Please describe.
Material has flags such as "has_roughness_texture" and "has_roughness_constant", these flags aren't required, since if there's no texture it will use the constant.

Describe the solution you'd like
Remove has_x_constant.

Describe alternatives you've considered
Additional context
N.A.

[Nielsbishere]

Material doesn't even need these flags (only on the GPU). You could just check if it has a textureptr