Switch to using custom RedirectUtils adapted from Keycloak

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

@@ -12,8 +12,8 @@
import org.keycloak.protocol.cas.mappers.CASAttributeMapper;
import org.keycloak.protocol.cas.representations.CASErrorCode;
import org.keycloak.protocol.cas.utils.CASValidationException;
import org.keycloak.protocol.cas.utils.RedirectUtils;
import org.keycloak.protocol.oidc.utils.OAuth2Code;
import org.keycloak.protocol.oidc.utils.RedirectUtils;
import org.keycloak.services.managers.AuthenticationManager;
import org.keycloak.services.managers.UserSessionCrossDCManager;
import org.keycloak.services.util.DefaultClientSessionContext;

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

@@ -12,7 +12,7 @@
import org.keycloak.models.KeycloakSession;
import org.keycloak.protocol.AuthorizationEndpointBase;
import org.keycloak.protocol.cas.CASLoginProtocol;
import org.keycloak.protocol.oidc.utils.RedirectUtils;
import org.keycloak.protocol.cas.utils.RedirectUtils;
import org.keycloak.services.ErrorPageException;
import org.keycloak.services.messages.Messages;
import org.keycloak.services.util.CacheControlUtil;

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

@@ -10,7 +10,7 @@
import org.keycloak.models.RealmModel;
import org.keycloak.models.UserSessionModel;
import org.keycloak.protocol.cas.CASLoginProtocol;
import org.keycloak.protocol.oidc.utils.RedirectUtils;
import org.keycloak.protocol.cas.utils.RedirectUtils;
import org.keycloak.services.ErrorPage;
import org.keycloak.services.managers.AuthenticationManager;
import org.keycloak.services.messages.Messages;