Downloads the json and core_functions DuckDB extensions into the local
extension directory (network). Run once per machine / CI runner; after
that, Schema.apply/1 only LOADs from disk and tests stay offline.
Downloads the json and core_functions DuckDB extensions into the local
extension directory (network). Run once per machine / CI runner; after
that, Schema.apply/1 only LOADs from disk and tests stay offline.