doc: improve CCM example

Applications should never attempt to use the deciphered message
if authentication fails. In reality, this is usually not a problem
since OpenSSL does not disclose the plaintext in this case, but it
is still a design mistake and can lead to critical security problems
in other cipher modes and implementations.

PR-URL: https://github.com/nodejs/node/pull/27396


Reviewed-By: Sam Roberts <vieuxtech@gmail.com>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Rich Trott <rtrott@gmail.com>