Does Istio have a dashboard similar to https://github.com/kubernetes/dashboard yet?
yes it has kiali dashboard.you can see istio configurations over there and also visualize istio mesh.
you can refer the below official documentation for same.
While it's not quite the same as the Kubernetes dashboard, Istio does come bundled with Grafana, which provides a UI for visualizing Istio metrics (via Prometheus).
See Istio's documentation for how to access: https://istio.io/docs/tasks/telemetry/using-istio-dashboard/
TL;DR, run this command: kubectl -n istio-system port-forward $(kubectl -n istio-system get pod -l app=grafana -o jsonpath='{.items[0].metadata.name}') 3000:3000
then navigate here for the dashboard: http://localhost:3000/dashboard/db/istio-mesh-dashboard
A relatively new project called Kiali aims to provide a UI to observe Istio service mesh.