Add Kiali port 20001 to istio-ingress to allow auth redirection
What
During oauth authentication process, kiali is redirecting to an url which uses the kiali port 20001: https://kiali.pre.gitlab.net:20001/
We need to open this port on the istio-ingress for the redirect to work.
Why
Related Issue: https://gitlab.com/gitlab-com/gl-infra/reliability/-/issues/24364