[App-server] v2 for account/updated and account/logout (#6175)

V2 for `account/updated` and `account/logout` for app server. correspond
to old `authStatusChange` and `LogoutChatGpt` respectively. Followup PRs
will make other v2 endpoints call `account/updated` instead of
`authStatusChange` too.

codex-rs/app-server/tests/suite/mod.rs

@@ -13,3 +13,4 @@ mod send_message;
 mod set_default_model;
 mod user_agent;
 mod user_info;
+mod v2;