Log to info when performing attribute sanitization (#3729)

It is quite common for CAS to perform attribute sanitization, therefore it should
not be logged as a warning.

core/cas-server-core-services-authentication/src/main/java/org/apereo/cas/authentication/support/DefaultCasProtocolAttributeEncoder.java

@@ -71,7 +71,7 @@ private static void sanitizeAndTransformAttributeNames(final Map<String, Object>
             .collect(Collectors.toSet());
 
         if (!attrs.isEmpty()) {
-            LOGGER.warn("Found [{}] attribute(s) that need to be sanitized/encoded.", attrs);
+            LOGGER.info("Found [{}] attribute(s) that need to be sanitized/encoded.", attrs);
             attributes.keySet().removeIf(getSanitizingAttributeNamePredicate());
             attrs.forEach(p -> {
                 val key = p.getKey();