Make GitHub Actions E2E tests independent of S3 secrets

[ChengShi-1]

Summary

Fork-based pull requests cannot run the full E2E suite because the GitHub Actions workflow requires S3_ACCESS_KEY and S3_SECRET_KEY.

S3-dependent tests include:

• FileUpload.spec.ts
• FileJSDataverseRepository.spec.ts
• Dataset.spec.tsx
• File.spec.tsx
• EditFileMetadata.spec.tsx
• CollectionItemsPanel.spec.ts

We could make E2E storage self-contained and independent of repository secrets—for example, use a local service instead.

[pdurbin]

I would suggest using LocalStack, which we added to the backend in this PR:

• add S3 tests, LocalStack, MinIO dataverse#10044

You'll find MinIO in the pull request as well, but we later removed it in this one:

• Replace MinIO with LocalStack as an S3 storage option  dataverse#12394

Here's where we switched LocalStack from Jenkins to GitHub Actions:

• 12367 GitHub actions workflow for jenkins redundancy dataverse#12368