Allow helm chart to specify dnsPolicy

[Argannor]

What happened?

The same issue as #5469: When running Crossplane with hostNetwork: true it is unable to resolve the DNS entries of functions, because the kubernetes default dnsPolicy (ClusterFirst) falls back to Default for pods in the hostNetwork (see Pod DNS Policy) and thus doesn't ask the cluster DNS.

Unfortunately the Helm chart doesn't allow users to set the dnsPolicy to anything else.

I will provide a pull request with the necessary changes soon.

How can we reproduce it?

1. Deploy Crossplane with hostNetwork: true
2. Deploy a Function and try to use it

What environment did it happen in?

• Crossplane version: 1.15.0
• Kubernetes: 1.29
• Cloud Provider: AWS
• Kubernetes distribution: EKS
• CNI: Calico
• OS: Linux