nginx: QUIC: Fix SSL 3.0 deprecated function

nginx: QUIC: Fix SSL 3.0 deprecated function

`EVP_CIPHER_CTX_cipher()` function was deprecated in OpenSSL 3.0.
As per OpenSSL's recommendation (https://www.openssl.org/docs/manmaster/man3/EVP_CIPHER_CTX_get0_cipher.html)
switch to using `EVP_CIPHER_CTX_get0_cipher()` instead.

With this change and recent commit to nginx-util #23935. We should now
be able to build nginx + modules with fully compliant calls to OpenSSL
3.0+ with legacy features disabled.

Signed-off-by: Sean Khan <datapronix@protonmail.com>
Link: https://github.com/openwrt/packages/pull/24005
Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>