[Feature] Fleet: Multi-cluster updates support full upgrades for AKS clusters using node auto-provisioning (NAP)

As a fleet administrator I want to be able to delegate automated full cluster updates for my AKS clusters that use [node auto-provisioning (NAP)](https://learn.microsoft.com/azure/aks/node-auto-provisioning) to Fleet Manager so that I can be confident that all my AKS clusters are updated through the same mechanism.

**Additional context**

Node auto-provisioning (NAP) provides a different upgrade experience to traditional AKS node pools ([see docs](https://learn.microsoft.com/en-us/azure/aks/node-auto-provisioning-upgrade-image)). The impact of this difference is it isn't possible to perform these upgrade types via Fleet Manager today:

1. "Full cluster" upgrades (Control + Node Pools).
2. "Node Image only" upgrades (just node pools).

Note: you can still perform Control Plane Only updates. NAP will manage the update of node images in this instance.