Add link to open merge requests on label index

Closes #13501 (closed)

Preview

Reassigned to @jschatz1

Looks good to me. I think we should have a rails person at this. Paging @rymai can you take a look and let me know if you approve? If so feel free to merge.

Reassigned to @rymai

@alfredo1 @jschatz1 LGTM. Handing this to @rspeicher for final review.

Reassigned to @rspeicher

mentioned in commit 076956cb

Status changed to merged