With SSL_VERIFY_PEER client RPK should abort on X509 error

With SSL_VERIFY_PEER client RPK should abort on X509 error

While RPK performs X.509 checks correctly, at the SSL layer the
SSL_VERIFY_PEER flag was not honoured and connections were allowed to
complete even when the server was not verified.  The client can of
course determine this by calling SSL_get_verify_result(), but some
may not know to do this.

Added tests to make sure this does not regress.

Fixes CVE-2024-12797

Reviewed-by: Tomas Mraz <tomas@openssl.org>
Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: Neil Horman <nhorman@openssl.org>