Fix the return value for SSL_get0_chain_certs()

This function was always returning 0. It should return 1 on success.

Fixes #9374

Reviewed-by: Kurt Roeckx <kurt@roeckx.be>
(Merged from https://github.com/openssl/openssl/pull/9395)

(cherry picked from commit 7bc82358ae930cfbd353602bc1fd25bfad107350)