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fix issue(#52244)kubectl describe serviceaccount have redundance null…

… line, we should keep accordance for kubectl describe command



**What this PR does / why we need it**:
close issue #52244

**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close that issue when PR gets merged)*: fixes #

**Special notes for your reviewer**:

**Release note**:

```release-note
NONE
```