empty lists shouldn't be interpreted by the client as an empty response

[gebhardtr]

Steps to reproduce:

1. Configure your MCP client to use the oracle.oci-network-load-balancer-mcp-server MCP server
2. Ask your model to list all network balancers in an OCI compartment that doesn't contain network load balancers.

Results:

The list_network_load_balancers tool call did not return a response. This could be due to a timeout or an issue with the MCP server.

Expected results:

There are no network load balancers in compartment $compartment