crypto: make ConvertKey clear openssl error stack

Failed ConvertKey() operations should not leave errors on OpenSSL's
error stack because that's observable by subsequent cryptographic
operations. More to the point, it makes said operations fail with
an unrelated error.

PR-URL: https://github.com/nodejs/node/pull/26153
Fixes: https://github.com/nodejs/node/issues/26133


Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Daniel Bevenius <daniel.bevenius@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>