Bump optimum-intel[nncf,openvino] from 1.12.4 to 1.15.2 in /image_generation/stable_diffusion_1_5/cpp/scripts

Bump optimum-intel[nncf,openvino] from 1.12.4 to 1.15.2 in /image_generation/stable_diffusion_1_5/cpp/scripts #19