chore: add exempt issue labels to stale cleaner config (#1617)

Signed-off-by: Anant Sharma <anants@nvidia.com>

.github/workflows/stale_cleaner.yml

@@ -27,11 +27,12 @@ jobs:
     steps:
       - uses: actions/stale@v9
         with:
-          stale-issue-message: 'This issue is stale because it has been open 30 days with no activity. Remove stale label or comment or this will be closed in 5 days.'
+          stale-issue-message: 'This issue is stale because it has been open 30 days with no activity. Remove stale label or comment or this will be closed in 5 days. As a reminder, please use backlog label to avoid issues being marked as stale.'
           close-issue-message: 'This issue has been closed due to inactivity. If you believe this issue is still relevant, please feel free to reopen it with additional context or information.'
           stale-pr-message: 'This PR is stale because it has been open 30 days with no activity. Remove stale label or comment or this will be closed in 5 days.'
           close-pr-message: 'This PR has been closed due to inactivity. If you believe this PR is still relevant, please feel free to reopen it with additional context or information.'
           delete-branch: true
           days-before-stale: 30
           days-before-close: 5
-          any-of-issue-labels: 'bug'
+          any-of-issue-labels: 'bug'
\ No newline at end of file
+          exempt-issue-labels: 'backlog'