Add unit tests for CloneSet creation logic

[GautamBytes]

This PR introduces unit tests for the resource creation logic located in pkg/creation/cloneset/cloneset_creation.go.

Reason for Change:
To ensure the reliability and correctness of the logic that converts a Deployment into a CloneSet, and to prevent future regressions.

Key Changes:
A new test file, cloneset_creation_test.go, has been added.
It utilizes the fake.Client from controller-runtime to provide a mock Kubernetes client, isolating the logic from a live API server.

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