Unable to add Nodepool with no availability zone

[cpinjani]

Setup
Rancher version: v2.11-1d345932e5f78b3da07ebe13691c8224c62b6240-head
AKS Operator version: v1.11.0-rc.3

Description
Adding Nodepool to AKS cluster without selecting any availability zone resulting into error:
Changing availability zones for node pool [pool1] in cluster [cpinjani-west (id: c-qlkpq)] is not permitted

Steps to reproduce:

• Create a cluster in region with AZ support Eg. EastUS
• Wait for cluster to be active and Edit cluster
• Add nodepool and do not select any availability zone

[vivek-shilimkar]

Validated on rancher v2.12-3a11b40d6d60d17279b22eaf9aedcfcebe80c6d4-head

• Created AKS v1.32.0 cluster
• Once cluster came into Active state added another node pool without any availability zone.
• Cluster came into Active state with a new node pool.