Similar to https://github.com/opengeospatial/geopackage/issues/319 and https://github.com/opengeospatial/geopackage/issues/336, the [CRS WKT](http://www.geopackage.org/spec/#extension_crs_wkt) extension lacks a requirement that the extension be registered. Ref: https://github.com/opengeospatial/ets-gpkg12/issues/10 h/t: @rouault
