Pre-exit hooks run more than once on pods with multiple containers

Hi, I noticed that when I have more than one container in a pod then the pre-exit hooks run on each container. The docs on pre-exit hooks say `Runs before the job finishes. Useful for performing cleanup tasks.` which is what I want in this case, not to have it run multiple times within the same job.

It seems like if I did want a hook to run on each container after the command finishes, then a post-command hook should do that. But this pre-exit hook behaviour seems like a bug -- let me know your thoughts!