Should we remove `cql-json` support in Filter extension?

`cql-json` is not advertised in https://github.com/stac-api-extensions/filter and OGC spec only support `cql2-text` and `cql2-json` https://docs.ogc.org/is/19-079r2/19-079r2.html#filter-lang-param

Should we remove it? 

cc @bitner @jonhealy1 @gadomski 