Tweak log level to avoid spamming log (opensearch-project#7232)

This is a common case and info level logging will result in a ton of
unhelpful log entries.

Signed-off-by: Andrew Ross <andrross@amazon.com>

server/src/main/java/org/opensearch/cluster/routing/allocation/allocator/RemoteShardsBalancer.java

@@ -207,7 +207,7 @@ void balance() {
         logger.trace("Performing balancing for remote shards.");
 
         if (remoteRoutingNodes.isEmpty()) {
-            logger.info("No eligible remote nodes found to perform balancing");
+            logger.debug("No eligible remote nodes found to perform balancing");
             return;
         }