Client-side NM graceful decom is not triggered when jobs finish

I was testing the client-side NM graceful decommission and noticed that it was always waiting for the timeout, even if all jobs running on that node (or even the cluster) had already finished.

For example:

1. JobA is running with at least one container on NodeA
2. User runs client-side decom on NodeA at 5:00am with a timeout of 3 hours --> NodeA enters DECOMMISSIONING state
3. JobA finishes at 6:00am and there are no other jobs running on NodeA
4. User's client reaches the timeout at 8:00am, and forcibly decommissions NodeA

NodeA should have decommissioned at 6:00am.