Blender Git Loki

Fix #32522: Object's diffuse color not showing in Sculpt Mode

It was missing since sculpting mask implementation.

Now object's color would be multiplied by sculpt mask value.

For VBOs it's done by storing final color in VertexBufferFormat and
mimic behavior of setMaterial callback for getting current diffuse
color.

For non-VBOs diffuse color is getting from current OpenGL context.