implement isRemoteClusterConnection and invoke it instead resolving alias

Author: slobodanadamovic

x-pack/plugin/security/src/main/java/org/elasticsearch/xpack/security/transport/CrossClusterAccessTransportInterceptor.java

@@ -330,7 +330,9 @@ private static IllegalArgumentException illegalArgumentExceptionWithDebugLog(Str
 
     @Override
     public boolean isRemoteClusterConnection(Transport.Connection connection) {
-        return false;
+        return remoteClusterCredentialsResolver.apply(connection)
+            .map(RemoteConnectionManager.RemoteClusterAliasWithCredentials::clusterAlias)
+            .isPresent();
     }
 
     @Override

x-pack/plugin/security/src/main/java/org/elasticsearch/xpack/security/transport/SecurityServerTransportInterceptor.java

@@ -144,12 +144,11 @@ public <T extends TransportResponse> void sendRequest(
                 TransportResponseHandler<T> handler
             ) {
                 assertNoCrossClusterAccessHeadersInContext();
-                final Optional<String> remoteClusterAlias = remoteClusterCredentialsResolver.apply(connection)
-                    .map(RemoteClusterAliasWithCredentials::clusterAlias);
+                final boolean isRemoteClusterConnection = remoteClusterTransportInterceptor.isRemoteClusterConnection(connection);
                 if (PreAuthorizationUtils.shouldRemoveParentAuthorizationFromThreadContext(
                     action,
                     securityContext,
-                    remoteClusterAlias.isPresent()
+                    isRemoteClusterConnection
                 )) {
                     securityContext.executeAfterRemovingParentAuthorization(original -> {
                         sendRequestInner(