[Network] az network vnet list-available-ips: support list available ips in a vnet#12371

mmyyrroonn merged 2 commits intoAzure:devAzure/azure-cli:devfrom

mmyyrroonn:fix-6876-free-ip-in-vnetmmyyrroonn/azure-cli:fix-6876-free-ip-in-vnetCopy head branch name to clipboard