Automatic merge from submit-queue (batch tested with PRs 56208, 55690). 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: rename flag to --ignore-preflight-errors

**What this PR does / why we need it**:
Addresses comments in #56072
Improves user experience by using name that is more
descriptive.

**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#480

**Special notes for your reviewer**:
/area kubeadm
/sig cluster-lifecycle
/assign @timothysc

**Release note**:
```release-note
NONE
```