doc: remove "is recommended from crypto legacy API text

The text for the legacy API sends mixed signals. It's legacy, but still
supported, so not deprecated, but not recommended. Let's begin to
clarify this by removing "not recommended". If we want to not-recommend
it, let's doc-deprecate it properly, or at least include an explanation
as to why it's not recommended.

PR-URL: https://github.com/nodejs/node/pull/34697


Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Ujjwal Sharma <ryzokuken@disroot.org>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>