Normalize text output to match new ns/name format instead of legacy name.ns

[clsacramento]

(This is used to request new product features, please visit https://discuss.istio.io for questions on using Istio)

Describe the feature request

When we create istio objects or as part of the analyze output, we get messages that some reference is not according to the correct for mat. For example, see this istioctl analyze output:

$ ./istio-1.11.2/bin/istioctl analyze -n demo
Error [IST0101] (VirtualService vs-frontend.demo) Referenced gateway not found: "ingress-http.common-gateway"
Error [IST0101] (VirtualService vs-frontend.demo) Referenced host not found: "frontend"
Warning [IST0132] (VirtualService vs-frontend.demo) one or more host [10.124.1.249 34.65.56.43.nip.io] defined in VirtualService demo/vs-frontend not found in Gateway demo/ingress-http.common-gateway.
Warning [IST0133] (VirtualService vs-frontend.demo) Schema validation warning: using legacy gatewayName format "ingress-http.common-gateway"; prefer the <namespace>/<name> format: "common-gateway/ingress-http"
Info [IST0102] (Namespace demo) The namespace is not enabled for Istio injection. Run 'kubectl label namespace demo istio-injection=enabled' to enable it, or 'kubectl label namespace demo istio-injection=disabled' to explicitly mark it as not needing injection.
Error: Analyzers found issues when analyzing namespace: demo.
See https://istio.io/v1.11/docs/reference/config/analysis for more information about causes and resolutions.

While it complains that "ingress-http.common-gateway" should prefer the / format, the message itself references "VirtualService vs-frontend.demo" which is also in the legacy format.

For consistency, the message should report "VirtualService demo/vs-frontend" instead.

Describe alternatives you've considered

Affected product area (please put an X in all that apply)

[ ] Docs
[ ] Installation
[ ] Networking
[ ] Performance and Scalability
[ ] Extensions and Telemetry
[ ] Security
[ ] Test and Release
[x] User Experience
[ ] Developer Infrastructure

Affected features (please put an X in all that apply)

[ ] Multi Cluster
[ ] Virtual Machine
[ ] Multi Control Plane

Additional context