fix(istio): Add line to allow enabling/disabling individual ingress gateways

Bug Fix

Description

Previously, if running using the tests/test-values.yaml with k3d-dev.sh and no flags, an behavior would sometimes occur that would assign all of the k3d/docker IP addresses to the passthrough-ingressgateway LoadBalancer service that is created using the test-values.yaml and assign none of the IP addresses to the public-ingressgateway LoadBalancer service. This would make the public-ingressgateway LoadBalancer service end up in a state and never be able to be used by incoming traffic. This was only occasionally seen since it is an undefined race condition (k3d/k3s doesn't define the behavior when deploying multiple LoadBalancers to the same cluster without using MetalLB).

This MR adds a line to allow passing enabled status for individual ingress gateways in istio. This would allow users/devs to turn off the extra passthrough-ingressgateway LoadBalancer service if they do not need it and are not running with MetalLB (e.g. using k3d-dev.sh with no flags).

For Issue

Closes 2118

Upgrade Notices

N/A