text: Title: Add e2e test for `tune` in the `katib_client` module
  Body: ### What you would like to be added?
  
  We need to add e2e test for the `tune` function in the `katib_client` module.
  
  ### Why is this needed?
  
  **References**
  - e2e test for `create_experiment` in the `katib_client` module: https://github.com/kubeflow/katib/blob/master/test/e2e/v1beta1/scripts/gh-actions/run-e2e-experiment.py#L172
  - e2e test for `training-operator` SDK: https://github.com/kubeflow/training-operator/blob/master/sdk/python/test/e2e/test_e2e_pytorchjob.py#L174
  
  **Source**
  - https://github.com/kubeflow/katib/pull/2325#issuecomment-2186646927
  
  **Related issues**
  - [Add unit tests to the Katib SDK #2184](https://github.com/kubeflow/katib/issues/2184)
  - [Add unit test for create_experiment in the katib_client module #2325](https://github.com/kubeflow/katib/pull/2325)
  - [Add unit test for tune in the katib_client module #2372](https://github.com/kubeflow/katib/issues/2372)
  
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