Customer feedback | az aks create | incorrect example

### Describe the bug

This GitHub issue is being created in response to customer feedback reported via Microsoft Outlook by @schaffererin.

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... we recently received a customer issue from CSS engineering regarding an AKS CLI command in [az aks | Microsoft Learn](https://learn.microsoft.com/en-us/cli/azure/aks) that refers to an unsupported scenario.

Under [examples](https://learn.microsoft.com/en-us/cli/azure/aks#az-aks-create-examples), the fourth command down to “Create a kubernetes cluster with k8s 1.13.9 but use vmas” is unsupported and should be removed.
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CCing @dyu1208, @FumingZhang, @andyliuliming on the Service Contact List.

### Related command

az aks create

### Errors

n/a

### Issue script & Debug output

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### Expected behavior

n/a

### Environment Summary

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### Additional context

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