[Github] Revert labeller update in new PRs workflow

This was causing workflow failures when PRs were opened. Revert the upgrade
for now so that this can be investigated and fixed before relanding.

Author: boomanaiden154

.github/workflows/new-prs.yml

@@ -67,7 +67,7 @@ jobs:
       github.event.pull_request.draft == false &&
       github.event.pull_request.commits < 10
     steps:
-      - uses: actions/labeler@634933edcd8ababfe52f92936142cc22ac488b1b # v6.0.1
+      - uses: actions/labeler@ac9175f8a1f3625fd0d4fb234536d26811351594 # v4.3.0
         with:
           configuration-path: .github/new-prs-labeler.yml
           # workaround for https://github.com/actions/labeler/issues/112