Allow scaling of workload clusters if there are critical updates available.

**Title**: Allow scaling of workload cluster nodepools if there are critical updates available.

**Description**: I wanted to scale up nodepools of a workload cluster with `Set-AksHciNodePool -clusterName -name -count ` and got stopped by an error message to do a critical upgrade first.

It would be nice to allow nodepool scaling if there are any critical upgrades available but not installed yet. In case of running out of resources, being forced to do a cluster upgrade first can cause serious trouble. In situations where peak loads are coming in not being able to scale up nodespools because updates had been published recently can be an unpleasant surprise.

Start with the Set-AksHciNodePool command path, especially the nodepool scaling flow that currently blocks when critical updates are available. Reproduce the reported case with a workload cluster and an available critical update, then verify that changing the nodepool count succeeds without first installing the update.

Written by the indexing model from the issue text.