Set DNS Server for private Deployment Script

**Is your feature request related to a problem? Please describe.**
If you use an NVA, in my case Azure Firewall as proxy for Azure DNS Private Resolver, as a DNS Server setup in the VNET, the underlying container instance used by the deployment script will still use Azure DNS (168.63.129.16). So if you follow [Private Link and DNS integration at scale
](https://learn.microsoft.com/en-us/azure/cloud-adoption-framework/ready/azure-best-practices/private-link-and-dns-integration-at-scale) you still have to link every single private DNS zone you need the script to use.

**Describe the solution you'd like**
Expose `dnsNameServers`, which I understand will point the container instance to the preferred DNS Server or, even better, use the DNS Server specified in the VNET.