Bump dawidd6/action-download-artifact from 9 to 11 (element-hq#18556)

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

.github/workflows/docs-pr-netlify.yaml

@@ -14,7 +14,7 @@ jobs:
       # There's a 'download artifact' action, but it hasn't been updated for the workflow_run action
       # (https://github.com/actions/download-artifact/issues/60) so instead we get this mess:
       - name: 📥 Download artifact
-        uses: dawidd6/action-download-artifact@07ab29fd4a977ae4d2b275087cf67563dfdf0295 # v9
+        uses: dawidd6/action-download-artifact@ac66b43f0e6a346234dd65d4d0c8fbb31cb316e5 # v11
         with:
           workflow: docs-pr.yaml
           run_id: ${{ github.event.workflow_run.id }}