Helper allows ingressApplicationGateway=true even if custom networking=false

[Gordonby]

Feedback from Cloud Native Hack Hours

Describe the bug

{"code": "InvalidTemplateDeployment", "message": "The template deployment 'main' is not valid according to the validation procedure. The tracking id is 'aba66ce8-6268-4e8a-afc3-c1541468703c'. See inner errors for details."} Inner Errors: {"code": "IngressAppGwAddonConfigInvalidSubnetCIDRNotContainedWithinVirtualNetwork", "message": "Provisioning of resource(s) for container service aks-az-k8s-9tin in resource group innerloop failed. Message: Category: ClientError; Code: IngressAppGwAddonConfigInvalidSubnetCIDRNotContainedWithinVirtualNetwork; SubCode: ; Message: Subnet Prefix '10.2.0.0/16' specified for IngressApplicationGateway addon is not contained within the AKS Agent Pool's Virtual Network address prefixes '[10.224.0.0/12]'.; InnerMessage: ; Dependency: ; OrginalError: %!s(); AKSTeam: . Details: "}

To Reproduce

az deployment group create -g innerloop  --template-uri https://github.com/Azure/AKS-Construction/releases/download/0.8.9/main.json --parameters \
	resourceName=az-k8s-9tin \
	ingressApplicationGateway=true

[Gordonby]

In the DeployTab.js logic, we need to check the value of the Networking model before adding the ingressApplicationGateway parameter to the textbox.

This behaviour will enforce the warning that is provided on the tab.

[Gordonby]

The problem is in the bicep, not the ui