stale bot: also close draft PRs that are too old

PiperOrigin-RevId: 757641325
Change-Id: I8f244e52cb07836fc4a9c7afde950469a93f40f1

Author: meteorcloudy

.github/workflows/stale.yml

@@ -52,6 +52,6 @@ jobs:
         close-issue-reason: "not_planned"
         stale-pr-label: 'stale'
         exempt-pr-labels: 'not stale,awaiting-review,awaiting-PR-merge,P0,P1,P2'
-        exempt-draft-pr: true
+        exempt-draft-pr: false
         operations-per-run: 500
         ascending: true