[Feature] VMSS Node Pool In-Place Resize

You can now resize the VM size (SKU) of an existing VMSS-based node pool in a single command using az aks nodepool update --node-vm-size .

When you trigger this update, the AKS resource provider performs a rolling upgrade by:

- Surging new nodes with the target VM size.
- Cordoning and draining the old nodes.
- Deleting the old nodes.

This avoids the manual create/cordon/drain/delete workflow.

[ms learn doc]https://learn.microsoft.com/en-us/azure/aks/resize-node-pool?tabs=azure-cli#resize-a-vmss-node-pool-in-place-preview