Enabling KEDA fails as it's behind a preview flag

Describe the bug Enabling KEDA fails as it’s behind a preview flag

To Reproduce Steps to reproduce the behavior:

1. Go to Addon Details
2. Enable “KEDA : Enable Kubernetes Event-driven Autoscaling (KEDA) on the AKS Cluster”

{ "status": "Failed", "error": { "code": "BadRequest", "message": "Feature Microsoft.ContainerService/AKS-KedaPreview is not enabled. Please see https://aka.ms/aks/previews for how to enable features." } }

Expected behavior Setup the Preview flag OR warn the user that it needs to enable the preview flag for KEDA : https://docs.microsoft.com/en-us/azure/aks/keda-deploy-add-on-arm#register-the-aks-kedapreview-feature-flag

az feature register --name AKS-KedaPreview --namespace Microsoft.ContainerService Screenshots

[naioja]

For example for KEDA if it’s enabled as a deployment feature we can add a check if the provider is enabled az feature list -o table --query "[?contains(name, 'Microsoft.ContainerService/AKS-KedaPreview')].{Name:name,State:properties.state}" and if that’s false then user can enable it: az feature register --name AKS-KedaPreview --namespace Microsoft.ContainerService

[Gordonby]

Yep. I think we can probably add an extra link to the Helper (that you mentioned above) to give users a steer 👍