evp_get_digest/cipherbyname_ex(): Try to fetch if not found

If the name is not found in namemap, we need
to try to fetch the algorithm and query the
namemap again.

Fixes #19338

Reviewed-by: Neil Horman <nhorman@openssl.org>
Reviewed-by: Paul Dale <ppzgs1@gmail.com>
Reviewed-by: Shane Lontis <shane.lontis@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/24940)