Simplify token prefix validation in ProxyValidateEndpoint

 src/main/java/org/keycloak/protocol/cas/endpoints/ProxyValidateEndpoint.java

@@ -6,12 +6,10 @@
import jakarta.ws.rs.core.Response;
import java.util.Map;
import org.jboss.resteasy.annotations.cache.NoCache;
import org.keycloak.events.Errors;
import org.keycloak.events.EventBuilder;
import org.keycloak.events.EventType;
import org.keycloak.models.*;
import org.keycloak.protocol.cas.CASLoginProtocol;
import org.keycloak.protocol.cas.representations.CASErrorCode;
import org.keycloak.protocol.cas.representations.CASServiceResponse;
import org.keycloak.protocol.cas.utils.CASValidationException;
import org.keycloak.protocol.cas.utils.ContentTypeHelper;
@@ -35,14 +33,8 @@
        event.event(EventType.CODE_TO_TOKEN);

        try {
            String prefix = ticket.startsWith(CASLoginProtocol.PROXY_TICKET_PREFIX)? CASLoginProtocol.PROXY_TICKET_PREFIX:(
                ticket.startsWith(CASLoginProtocol.SERVICE_TICKET_PREFIX)? CASLoginProtocol.SERVICE_TICKET_PREFIX : null
            );

            if (prefix == null) {
                event.error(Errors.INVALID_CODE);
                throw new CASValidationException(CASErrorCode.INVALID_TICKET_SPEC, "Malformed service ticket", Response.Status.BAD_REQUEST);
            }
            String prefix = ticket != null && ticket.startsWith(CASLoginProtocol.PROXY_TICKET_PREFIX) ?
                    CASLoginProtocol.PROXY_TICKET_PREFIX : CASLoginProtocol.SERVICE_TICKET_PREFIX;

            checkSsl();
            checkRealm();