Merge pull request #52383 from dixudx/quote_field_valid_string
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>.
quote valid strings for field validation
**What this PR does / why we need it**:
Some of the declared const vars are empty string `""`, such as
* [`NamespaceAll`, `NamespaceNone`](https://github.com/kubernetes/kubernetes/blob/master/pkg/api/types.go#L197-L200)
* [`HostPathUnset`](https://github.com/kubernetes/kubernetes/blob/master/pkg/api/types.go#L631)
When validating such supported fields, empty string will be printed without quotes, which is kind of ugly.
**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close that issue when PR gets merged)*: fixes #53849
**Special notes for your reviewer**:
/assign @liggitt
**Release note**:
```release-note
None
```
7c75723867