Update Dex Login Test

[kunal-511]

Pull Request Template for Kubeflow Manifests

✏️ Summary of Changes

Fresh Session per Retry
Handle 401 Status Codes

📦 Dependencies

List any dependencies or related PRs (e.g., "Depends on #123").

🐛 Related Issues

Fix unstable dex oauth2 test

✅ Contributor Checklist

• I have tested these changes with kustomize. See Installation Prerequisites.
• All commits are signed-off to satisfy the DCO check.
• I have considered adding my company to the adopters page to support Kubeflow and help the community, since I expect help from the community for my issue (see 1. and 2.).

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[juliusvonkohout]

Thank you
/lgtm
/approve

there are some minor items to improve, but if it works then it is better than the status quo.

[google-oss-prow]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: juliusvonkohout

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