Remove cipher_ctx_get_cipher_kt and replace with direct context calls

Remove cipher_ctx_get_cipher_kt and replace with direct context calls

We currently have a number of calls that fetch the cipher_kt from a
cipher_ctx to then do a query on the cipher_kt. Directly fetching the
desired property from the context is cleaner and helps for using the
proper APIs with OpenSSL 3.0 and mbed TLS 3.0

Signed-off-by: Arne Schwabe <arne@rfc2549.org>
Acked-by: Gert Doering <gert@greenie.muc.de>
Message-Id: <20211201180727.2496903-3-arne@rfc2549.org>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg23278.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>