Exclude confirmed bugs from stale-tidy bot

We should not close confirmed bugs through a timeout mechanism. The bug
exists and should be tracked as open bug as long as we don't fix it or
explicitly decide to not handle this, in which case, we'd manually close
 as "won't fix".

Author: timhoffm

.github/workflows/stale-tidy.yml

@@ -20,5 +20,5 @@ jobs:
           close-issue-label: "status: closed as inactive"
           days-before-issue-close: 30
           ascending: true
-          exempt-issue-labels: "keep"
+          exempt-issue-labels: "keep,status: confirmed bug"
           exempt-pr-labels: "keep,status: orphaned PR"