[llvm] [workflows] Update commit access request PR links (PR #146169)

[David Peixotto via llvm-commits]

dmpots wrote:

> @dmpots Can we add is:merged to the query? That would be the most helpful, those are what actually count towards the requirements.

@tstellar do you mean that we should only have the one link that shows the merged PRs and not the separate link for total vs. merged?

It is currently adding the `is:merged` as a separate link
```
merged_prs_url = total_prs_url + "+is%3Amerged"
```

https://github.com/llvm/llvm-project/pull/146169