ci(bug): Fix workflow race condition

The error [here](https://github.com/hiero-ledger/hiero-consensus-node/actions/runs/22153755634/job/64052025875) is that the workflow deleted the xts-candidate tag, prepping to tag, around the same time [another instance](https://github.com/hiero-ledger/hiero-consensus-node/actions/runs/22153723324) of it tagged xts-candidate and pushed. When this workflow went to tag the commit as xts-candidate the tag existed again, causing a failure.

Re-running the job worked as a quick-bandage.

We need to investigate the race condition here and see if we can get around it.

Suggestion: Use github actions concurrency groups [[1]](https://docs.github.com/en/actions/how-tos/write-workflows/choose-when-workflows-run/control-workflow-concurrency) [[2]](https://docs.github.com/en/actions/reference/workflows-and-actions/workflow-syntax#concurrency)

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In parallel (not related) add the workflow link to the slack report.

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Definition of Done:
- [ ] Concurrency groups enabled (do not cancel in progress)
- [ ] Workflow link included in slack error report