Automatic merge from submit-queue
Improved code coverage for pkg/kubelet/types/labels
The test coverage improved from 0% to 100%.
This fixed part of #40780
**What this PR does / why we need it**:
Increase test coverage.
**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-none
**Release note**:
```NONE
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