efa94b06c2
`prs = response.json().get("items", [])` will return empty when there are no merged PRs, and this will just skip the all-label replacement process.
This is a regression following the work done in #19442
Adding another part to handle closed PRs (which is the majority of the cases we have in Scylla core)
Fixes: https://github.com/scylladb/scylladb/issues/19441
Closes scylladb/scylladb#19497