apps/cmp.c: fix cleanup of CMP_CTX vs. APP_HTTP_TLS_INFO in its http_cb_arg field

apps/cmp.c: fix cleanup of CMP_CTX vs. APP_HTTP_TLS_INFO in its http_cb_arg field

Prevent crashes on error by making sure the info is freed after OSSL_CMP_CTX_free(),
which may call OSSL_HTTP_close() and thus indirectly reference the info.
Moreover, should not attempt to reference the cmp_ctx variable when NULL.

Reviewed-by: Tomas Mraz <tomas@openssl.org>
Reviewed-by: Hugo Landau <hlandau@openssl.org>
Reviewed-by: David von Oheimb <david.von.oheimb@siemens.com>
(Merged from https://github.com/openssl/openssl/pull/18702)