test: Migrate Backend tests to a GHA workflow

[DharmitD]

Description of your changes:
Resolves #10867

Converts the Prow backend test to a GH Action Workflow.

Here's a working GH Action run on my fork: https://github.com/DharmitD/data-science-pipelines-argo/actions/runs/9390063669

Checklist:

• The title for your pull request (PR) should follow our title convention. Learn more about the pull request title convention used in this repository.

[google-oss-prow]

@DharmitD: The following test failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
kubeflow-pipeline-e2e-test	a85e8af	link	false	/test kubeflow-pipeline-e2e-test

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository. I understand the commands that are listed here.

[google-oss-prow]

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