Fix certificate version number in test

The version number 3 means version 4, while 2 means version 3. Since this is the v3nametest, version 3 should be used.

CLA: Trivial

Reviewed-by: Rich Salz <rsalz@openssl.org>
Reviewed-by: Richard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/3577)