Automatic merge from submit-queue. If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.

kubeadm init: skip checking cri socket in preflight checks

**What this PR does / why we need it**:
`kubeadm init` does not need to require `dockershim.sock` to be present.
Remove the check for `dockershim.sock`.
xref #55055

**Which issue(s) this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close the issue(s) when PR gets merged)*:
Fixes kubernetes/kubeadm#657

**Special notes for your reviewer**:
/area kubeadm
/kind bug
/assign @luxas 
/cc @kubernetes/sig-cluster-lifecycle-pr-reviews 

**Release note**:

```release-note
kubeadm init: skip checking cri socket in preflight checks
```