Automatic merge from submit-queue

kubeadm: Set the new BT auth group on the init token

**What this PR does / why we need it**:

What I forgot to do in https://github.com/kubernetes/kubernetes/pull/51956 😅 
When we now have the new group, we should also set it on the token, otherwise nodes can't be joined

On the good side, our CI testing broke https://k8s-testgrid.appspot.com/sig-cluster-lifecycle#kubeadm-gce
Great to see that it actually works :)

**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close that issue when PR gets merged)*: fixes #

**Special notes for your reviewer**:

**Release note**:

```release-note
NONE
```
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