gh-95095: Use SSL_CTX_get_max_proto_version instead of SSL_CTX_ctrl (GH-95096)

The wrapper macros are more readable and match the form recommended in
the OpenSSL documentation. They also slightly less error-prone, as the
mapping of arguments to SSL_CTX_ctrl is not always clear. (Though in
this case it's straightforward.)
https://www.openssl.org/docs/man1.1.1/man3/SSL_CTX_get_max_proto_version.html