Add hidden embedding parameters to the documentation (#15739)

* Update 13-embedding.md

* Update docs/administration-guide/13-embedding.md

Co-authored-by: Jeff Bruemmer <jeff@metabase.com>

* Update 13-embedding.md

* Update docs/administration-guide/13-embedding.md

Co-authored-by: Jeff Bruemmer <jeff@metabase.com>

* Update docs/administration-guide/13-embedding.md

Co-authored-by: Jeff Bruemmer <jeff@metabase.com>

Co-authored-by: Jeff Bruemmer <jeff@metabase.com>