If they are allowed to work with AI in the job then I would not say it’s an issue to use it in a take home test.
It helps our life, why not help the candidate as well? It will be discovered pretty soon if they do not know how is the submitted task working

I hate live coding, I was always nervous on interviews and forgot even trivial stuff if I felt the environment even a touch hostile. Take home tests was my favourite since it allowed me to relax and actually perform the way I do day to day.