New metafield jsonValue field

As of API version 2024-07, the Metafield and MetaobjectField objects now have a jsonValue field returning the stored value as a JSON scalar. This is particularly helpful for metafield values that are stored as JSON strings to avoid having to parse client-side. This field is set for all metafield types and is also available in all Function APIs. It can be used in Function input queries to improve function performance and reduce the instructions needed to parse JSON metafield values, which are commonly used for function configuration.