ingress-gateways installed in an application namespace cannot receive traffic from routers

ingress-gateways installed in an application namespace cannot receive traffic from routers.
This is due to the fact that the networkpolicy is not correctly setup.
Forcing the ingress pod to use this network policy: `istio-expose-route` via this label: `maistra.io/expose-route=true` does not work either due to a bug in how helm processes templates that prevents `'true'` from being treated as a string.