Automatic merge from submit-queue (batch tested with PRs 57127, 57011, 56754, 56601, 56483). 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>.
Enhance proxy mode validation
**What this PR does / why we need it**:
Proxy modes are list multiple times in validateProxyModeWindows and validateProxyModeLinux. This PR enhances the validation logic and only list them once.
**Which issue(s) this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close the issue(s) when PR gets merged)*:
Refer https://github.com/kubernetes/kubernetes/pull/56529/files#r156448205.
**Special notes for your reviewer**:
**Release note**:
```release-note
NONE
```
/assign @thockin
1f025dde30