Expose desired balance APIs internally in serverless (#106116)

These APIs are useful for troubleshooting, we should make them available
to internal users.

server/src/main/java/org/elasticsearch/rest/action/admin/cluster/RestDeleteDesiredBalanceAction.java

@@ -13,11 +13,14 @@ import org.elasticsearch.action.admin.cluster.allocation.TransportDeleteDesiredB
 import org.elasticsearch.client.internal.node.NodeClient;
 import org.elasticsearch.rest.BaseRestHandler;
 import org.elasticsearch.rest.RestRequest;
+import org.elasticsearch.rest.Scope;
+import org.elasticsearch.rest.ServerlessScope;
 import org.elasticsearch.rest.action.RestToXContentListener;
 
 import java.io.IOException;
 import java.util.List;
 
+@ServerlessScope(Scope.INTERNAL)
 public class RestDeleteDesiredBalanceAction extends BaseRestHandler {
 
     @Override

server/src/main/java/org/elasticsearch/rest/action/admin/cluster/RestGetDesiredBalanceAction.java

@@ -13,11 +13,14 @@ import org.elasticsearch.action.admin.cluster.allocation.TransportGetDesiredBala
 import org.elasticsearch.client.internal.node.NodeClient;
 import org.elasticsearch.rest.BaseRestHandler;
 import org.elasticsearch.rest.RestRequest;
+import org.elasticsearch.rest.Scope;
+import org.elasticsearch.rest.ServerlessScope;
 import org.elasticsearch.rest.action.RestRefCountedChunkedToXContentListener;
 
 import java.io.IOException;
 import java.util.List;
 
+@ServerlessScope(Scope.INTERNAL)
 public class RestGetDesiredBalanceAction extends BaseRestHandler {
 
     @Override