Remove lowercase for the hostname as recommended/advised by OAuth spec
Closes https://github.com/keycloak/keycloak/issues/25001

Signed-off-by: rmartinc <rmartinc@redhat.com>

 src/main/java/org/keycloak/protocol/cas/utils/RedirectUtils.java

@@ -72,10 +72,8 @@
            if (validRedirect.startsWith("/")) {
                validRedirect = relativeToAbsoluteURI(session, rootUrl, validRedirect);
                logger.debugv("replacing relative valid redirect with: {0}", validRedirect);
                resolveValidRedirects.add(validRedirect);
            } else {
                resolveValidRedirects.add(validRedirect);
            }
            resolveValidRedirects.add(validRedirect);
        }
        return resolveValidRedirects;
    }
@@ -148,7 +146,11 @@
                valid = matchesRedirects(resolveValidRedirects, redirectUri, false);
            }

            if (valid != null && redirectUri.startsWith("/")) {
            if (valid != null && !originalRedirect.isAbsolute()) {
                // return absolute if the original URI is relative
                if (!redirectUri.startsWith("/")) {
                    redirectUri = "/" + redirectUri;
                }
                redirectUri = relativeToAbsoluteURI(session, rootUrl, redirectUri);
            }

@@ -189,7 +191,6 @@
        String redirectUri = null;
        if (uri != null) {
            redirectUri = uri.normalize().toString();
            redirectUri = lowerCaseHostname(redirectUri);
        }
        return redirectUri;
    }
@@ -204,9 +205,11 @@
            KeycloakUriBuilder uriBuilder = KeycloakUriBuilder.fromUri(redirectUri, false).preserveDefaultPort();
            String origQuery = uriBuilder.getQuery();
            String origFragment = uriBuilder.getFragment();
            String origUserInfo = uriBuilder.getUserInfo();
            String encodedRedirectUri = uriBuilder
                    .replaceQuery(null)
                    .fragment(null)
                    .userInfo(null)
                    .buildAsString();
            String decodedRedirectUri = null;

@@ -217,6 +220,7 @@
                    return KeycloakUriBuilder.fromUri(decodedRedirectUri, false).preserveDefaultPort()
                            .replaceQuery(origQuery)
                            .fragment(origFragment)
                            .userInfo(origUserInfo)
                            .buildAsString();
                } else {
                    // Next attempt
@@ -230,15 +234,6 @@
        return null;
    }

    private static String lowerCaseHostname(String redirectUri) {
        int n = redirectUri.indexOf('/', 7);
        if (n == -1) {
            return redirectUri.toLowerCase();
        } else {
            return redirectUri.substring(0, n).toLowerCase() + redirectUri.substring(n);
        }
    }

    private static String relativeToAbsoluteURI(KeycloakSession session, String rootUrl, String relative) {
        if (rootUrl != null) {
            rootUrl = ResolveRelative.resolveRootUrl(session, rootUrl);