Blender Git Loki

Instead of raising an expection a warnign is generated instead.
This fixes the issue where `['hair', 'pointcloud']` are disabled for
release builds.
In the future a better solution would be to generate the context map
dynamically but this would require refactoring of the API: D9988

Fixes T80364

Differential revision: https://developer.blender.org/D10468