[FEATURE REQ] KubernetesClustersImpl.listKubernetesVersions(Region.WEST_EUROPE) differs from az aks get-versions --location west-europe

**Describe the bug**
The library function KubernetesClustersImpl.listKubernetesVersions() differs from the results that are given by `az aks get-versions --location west-europe`.

***Exception or Stack Trace***
None

**To Reproduce**
Steps to reproduce the behavior:
Execute function and `az aks get-versions --location west-europe`.

***Code Snippet***
`Azure.authenticate(credentials).withDefaultSubscription().kubernetesClusters().listKubernetesVersions(Region.EUROPE_WEST);`
`az aks get-versions --location west-europe --output table`

**Expected behavior**
I expect that the library is on-par with what the AZ cli gives, *or* that there is way to differentiate the results. In my case, I'm looking for the 'default' version, which the Azure Portal gives me (which is N-1 according to the docs). Using this library, I can't get the default version.

So it would be nice to have a function like: listKubernetesProductionVersions(Region.WEST_EUROPE), and a function like defaultKubernetesProductionVersion(Region.WEST_EUROPE).

**Screenshots**
None.

**Setup (please complete the following information):**
N/A

**Information Checklist**
Kindly make sure that you have added all the following information above and checkoff the required fields otherwise we will treat the issuer as an incomplete report
- [x] Bug Description Added
- [x] Repro Steps Added
- [x] Setup information Added

Start at KubernetesClustersImpl.listKubernetesVersions and compare its results with `az aks get-versions --location west-europe --output table`. Determine how the library should expose production and default Kubernetes versions, then verify that the behavior distinguishes the requested versions from the CLI and portal results.

Written by the indexing model from the issue text.