Change log level for log line in OBO Authenticator if OBO is disabled (…

…#4952)

Signed-off-by: Craig Perkins <[email protected]>

src/main/java/org/opensearch/security/http/OnBehalfOfAuthenticator.java

@@ -166,7 +166,7 @@ public AuthCredentials run() {
 
     private AuthCredentials extractCredentials0(final SecurityRequest request) {
         if (!oboEnabled) {
-            log.error("On-behalf-of authentication is disabled");
+            log.debug("On-behalf-of authentication is disabled");
             return null;
         }