Automatic merge from submit-queue (batch tested with PRs 60919, 60953, 61085, 61083, 60971). 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>.

remove unused `pkg/api/unversioned`

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

clean code, see #61084 

**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 #61084

**Special notes for your reviewer**:

**Release note**:

```release-note
NONE
```