ZITADEL: Missing Token Expiration (`exp`) Validation in JWT IdP Provider

ZITADEL is an open source identity management platform. Prior to 3.4.12 and 4.15.2, ZITADEL is an open source identity management platform. From 3.0.0-rc.1 through 3.4.11 and from 4.0.0-rc.1 through 4.15.1, ZITADEL's external JWT Identity Provider validation in internal/idp/providers/jwt/session.go skips expiration handling when an incoming token omits the exp claim, allowing a token from a trusted issuer to be treated as valid without an automatic expiration window. This issue is fixed in versions 3.4.12 and 4.15.2.