Add unit tests for statusViewer

[GautamBytes]

What this PR does / why we need it

This pull request introduces comprehensive unit tests for the statusViewer function within the pkg/internal/polymorphichelpers package. Currently, this function lacks test coverage, making it susceptible to future regressions.

The new tests verify the core logic by:

1. Confirming Success: Ensures a valid StatusViewer is returned for known resource kinds like apps/Deployment.
2. Verifying Failure: Ensures an error is returned for unknown resource kinds.
3. Handling Edge Cases: Explicitly tests that a nil input causes a panic, which is the current behavior of the function.

How to test this PR

This PR only adds a test file. The changes can be verified by running the test suite for the package:

go test ./pkg/internal/polymorphichelpers

[kruise-bot]

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