Function oklabToXYZ

Converts a color from OKLab to CIE XYZ color space.

This function implements the OKLab to XYZ conversion algorithm, which includes:

1. Converting OKLab to LMS cone responses using a transformation matrix
2. Applying a non-linear transformation (cubing) to the LMS values
3. Converting the non-linear LMS values to XYZ using another matrix