Fix encrypted attributes improperly casted

[Michaelvilleneuve]

This PR fixes a bug introduced by ActiveRecord::Encrypted attributes.
Instead of returning a ActiveModel::Type::String like they used to, encrypted attributes return an instance of ActiveRecord::Encryption::EncryptedAttributeType, on which you need to call #cast_type in order to obtain the original type.

To fix this, I check whether or not the attribute #responds_to?(:cast_type) which would indicate that we need to take into account the underlying type instead of just #type_for_attribute.

Checking this instead of checking if the attribute_name #responds_to?(:encrypted_attributes) allows to take into account other forms of type overriding that ActiveRecord may introduce in the future or potentially already exist.

See the type difference below between a regular string attribute and an encrypted attribute

Fixes #1829

[nashby]

@Michaelvilleneuve hey! Thanks for the PR! It looks like Rails bug to me so I've sent a PR fixing it rails/rails#52247 but I think it's ok to merge this for now.