Investigate user_init_lambda_zip built on every apply

This lambda zip is built on _every_ terraform apply. I'm not sure why; this commit purposefully add the functionality: https://github.com/Element84/filmdrop-aws-tf-modules/commit/4e59f0e46a3d8779d21585a44e3ce9dfd0bc7baf#diff-2f6d306a66599c619171f0a9cfae6204cd95294be732815b3fe297e8f4e0ebd4

Is this needed, and if so, why? If it's not needed, removing it would certainly be preferable.