Consider using `eps1lon/actions-label-merge-conflict` GitHub action to check merge conflicts

### Is your feature request related to a problem or challenge?

We have a TODO item in our labeler workflow:

https://github.com/apache/datafusion/blob/58bc7496bfdde37c6c1860634e0ef1d8b9b98921/.github/workflows/labeler.yml#L55-L65

I think we can use this action if we pin it to a specific hash, e.g.

https://github.com/apache/datafusion/blob/1629420162815e1a725b9be5344fafd1fbe2e5ff/.github/workflows/rust.yml#L755

### Describe the solution you'd like

Consider enabling this

### Describe alternatives you've considered

If we don't see value in having this action then remove the commented code

### Additional context

_No response_

Inspect .github/workflows/labeler.yml around lines 55-65 and the pinned-action example in .github/workflows/rust.yml around line 755. Determine whether to enable eps1lon/actions-label-merge-conflict at a specific hash or remove the commented TODO code; the workflow should clearly reflect the chosen direction.

Written by the indexing model from the issue text.