Remove redundant parse in address fields

The value is already parsed by the call to `super`. The `StructuredField` [initializer](https://github.com/mikel/mail/blob/17457e44596308d8092d340e372fb8a582bb66be/lib/mail/fields/structured_field.rb#L29) calls the [`value` setter](https://github.com/mikel/mail/blob/17457e44596308d8092d340e372fb8a582bb66be/lib/mail/fields/common/common_address.rb#L96) which parses the value.

I dug around to see if there was a reason for this but it just looks like the duplication was unintentionally added in edbe7861e75721f376f53dd51ca1a68c80a3573c