[FEATURE] - explore/keep eyes on BQ new JSON functions

BQ introduced a native JSON data type (ala variants in snowflake maybe?) and some new JSON parsing functions. the ones we leverage in this package are now "legacy" in the docs https://cloud.google.com/bigquery/docs/reference/standard-sql/json_functions

let's keep eyes on this to see if theres any sort of deprecation

Start with the linked BigQuery JSON functions documentation, then inspect this package for the JSON parsing functions described as legacy. Determine whether BigQuery has announced deprecation or migration guidance; the work is done when the risk is documented and a concrete follow-up change, if needed, is identified.

Written by the indexing model from the issue text.