Update the HA Ingress controller to wait until it sees AdvertisedServices
config propagated into at least 1 Pod's prefs before it updates the status
on the Ingress, to ensure the ProxyGroup Pods are ready to serve traffic
before indicating that the Ingress is ready
Updates tailscale/corp#24795
Change-Id: I1b8ce23c9e312d08f9d02e48d70bdebd9e1a4757
Signed-off-by: Tom Proctor <tomhjp@users.noreply.github.com>