allow classification annotations data types to persist via transport

Ensure the submitted classification annotations are serialised JSON. The DB adapters will persiste the annotation JSON data with their serialised types and they won't be converted to strings.
Strong params was rejecting the annotations param as it's not a scalar value. If it's not whitelisted then they are not allowed to be set, https://github.com/rails/strong_parameters#permitted-scalar-values.

Seemed to be the only workaround was to whitelist the annotation param. Happy to change if there's a better one.