Azure Arc connectedk8s support for arm64

### Extension name (the extension in question)
connectedk8s

### Description of issue (in as much detail as possible)
Configuration:
- Platform: Raspberry Pi 4
- OS: Ubuntu Server 20.10
- K8s: v1.19.4

I'm trying to enroll my Raspberry Pi 4 K8s cluster in Azure Arc:

`> az connectedk8s connect --name --resource-group --location eastus`

The enrollment times out and all pods report `FailedScheduling`:
```
> for pod in $(kubectl get pods -n azure-arc | grep 'Pending' | cut -d' ' -f1); do kubectl describe pod $pod -n azure-arc | grep FailedScheduling; done

Warning FailedScheduling 22m default-scheduler 0/5 nodes are available: 5 node(s) didn't match node selector.
Warning FailedScheduling 22m default-scheduler 0/5 nodes are available: 5 node(s) didn't match node selector.
Warning FailedScheduling 22m default-scheduler 0/5 nodes are available: 5 node(s) didn't match node selector.
Warning FailedScheduling 22m default-scheduler 0/5 nodes are available: 5 node(s) didn't match node selector.
Warning FailedScheduling 22m default-scheduler 0/5 nodes are available: 5 node(s) didn't match node selector.
Warning FailedScheduling 22m default-scheduler 0/5 nodes are available: 5 node(s) didn't match node selector.
Warning FailedScheduling 22m default-scheduler 0/5 nodes are available: 5 node(s) didn't match node selector.
Warning FailedScheduling 22m default-scheduler 0/5 nodes are available: 5 node(s) didn't match node selector.
Warning FailedScheduling 22m default-scheduler 0/5 nodes are available: 5 node(s) didn't match node selector.
Warning FailedScheduling 22m default-scheduler 0/5 nodes are available: 5 node(s) didn't match node selector.
Warning FailedScheduling 22m default-scheduler 0/5 nodes are available: 5 node(s) didn't match node selector.
Warning FailedScheduling 22m default-scheduler 0/5 nodes are available: 5 node(s) didn't match node selector.
Warning FailedScheduling 22m default-scheduler 0/5 nodes are available: 5 node(s) didn't match node selector.
Warning FailedScheduling 22m default-scheduler 0/5 nodes are available: 5 node(s) didn't match node selector.
```

Digging into the pod manifest, they are requesting amd64 nodes:

```
nodeSelector:
kubernetes.io/arch: amd64
kubernetes.io/os: linux
```

I'm running on arm64, and nodes a labeled as such (b/c I'm on Raspberry Pi):
```
labels:
beta.kubernetes.io/arch: arm64
beta.kubernetes.io/os: linux
kubernetes.io/arch: arm64
kubernetes.io/hostname: rpi4-02
kubernetes.io/os: linux
```

Is the amd64 node selector an oversight, or intentional? Does Azure Arc support arm64?
-----