Add support to ignore updates on autofollow pattern

[ankitkala]

Description

• Exception handling was added for Autofollow update in the change below but tests weren't handling it gracefully. Added a flag to ignore ResourceAlreadyExists exception.
• Also updated Github action to use upload-artifact@v4 and checkout action.

Related Issues

https://github.com/opensearch-project/cross-cluster-replication/issues/1433

Check List

• [ ] New functionality includes testing.
• [ ] New functionality has been documented.
• [ ] API changes companion pull request created.
• [ ] Commits are signed per the DCO using --signoff.
• [ ] Public documentation issue/PR created.

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