Api sends search requests with a size of `null` when using copy script

Summary

batchSize has no default value. So it gets parsed by parseInt to NaN. When it gets send in JSON it gets converted to null. null is definitly not a number that is why the new backend which validates all requests will reject those requests.

Steps to reproduce

Use the copy script on the new backend

Possible fixes

Add a default value to https://gitlab.com/openstapps/api/blob/master/src/cli.ts#L45