Automatic merge from submit-queue (batch tested with PRs 44687, 44689, 44661)

Fix panic when using `kubeadm init` with vsphere cloud-provider

**What this PR does / why we need it**:
Check if the reference is nil when finding machine reference by UUID.

**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close that issue when PR gets merged)*: fixes #44603

**Special notes for your reviewer**:
This is just a quick fix for the panic.

**Release note**:

```release-note
NONE
```