Feature request: support kstatus based health checking of HTTPProxies

[tsaarni]

Please describe the problem you have

Add support for clients to monitor health of HTTPProxies using heuristics defined by the kstatus library https://github.com/kubernetes-sigs/cli-utils/tree/master/pkg/kstatus

This is used by (among others)

• Helm (link, through flux fork of cli-utils)
• FluxCD (link)
• kpt

Originally submitted by @fergian94 as PR #7648

Problem
Since the introduction of kstatus in Helm 4, custom resources can now be monitored during install. For HTTPProxy and ExtensionService CRs, the Valid condition type is not recognized by kstatus logic,
which specifically looks for a Ready condition. This causes Helm to assume resources are immediately ready, defeating the purpose of --wait.