[Go] Transcode WKT to WKB for geometry/geography

https://github.com/adbc-drivers/bigquery/pull/134#pullrequestreview-3955890547

> It would be more widely accessible output if the WKT was reencoded as WKB by the driver (I think that geoarrow-pyarrow is possibly the only tool in existence that ever supported geoarrow.wkt). 