Update pytorch launcher component in Kubeflow Pipelines repository

[anishasthana]

The pytorch launcher component in the Kubeflow Pipelines repository hasn't been updated in a while. We should update the component to work with Pipelines v2 concepts and be better aligned with the latest version of the Kubeflow Training operator.

[andreyvelich]

/good-first-issue
/kind feature

[google-oss-prow]

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