OSSL_CMP_certConf_cb(): fix regression on checking newly enrolled cert

OSSL_CMP_certConf_cb(): fix regression on checking newly enrolled cert

Also add corresponding tests and to this end update credentials

Reviewed-by: Tomas Mraz <tomas@openssl.org>
Reviewed-by: Paul Dale <pauli@openssl.org>
Reviewed-by: David von Oheimb <david.von.oheimb@siemens.com>
(Merged from https://github.com/openssl/openssl/pull/20160)

(cherry picked from commit 6b58f498b3f5d8e4c9197c3c5228fb450e33aaaf)