The atlas proxy will disallow storageEngine and indexOptionDefaults options. Any user who is trying to restore or migrate a collection that has these options set won't be able to complete their restore.

We need to think about what workarounds we can provide users so that they don't get stuck if they need to restore a collection that has these options set.

Options:

a) just error

b) an option that will strip these collection options for them

c) tell users to edit their metadata (problem: there's no way to do this for archives currently)

I think an option to strip the options makes the most sense and lines up with our convert legacy indexes option.