This PR enables cubemap array extension in compute shaders when
supported by the platform. When used the shader must include
cubemap_lib as it contains a fallback implementation when
cubemap arrays aren't supported by the platform.
NOTE: This extension is available in Core Vulkan and doesn't need to be enabled.
Metal doesn't support cubemap arrays and would use the fallback.
Pull Request: https://projects.blender.org/blender/blender/pulls/109546
c2de379081