Increase thresholds for zombie processes
Increase thresholds for zombie processes

Previously we alerted for a really small number of <defunct> zombie
processes, which is not actually a problem, especially if we're
recycling machines fairly regularly. This increases the thresholds
to better indicate an issue i.e. if we run out of usable PIDs.

Reference: https://www.howtogeek.com/119815/htg-explains-what-is-a-zombie-process-on-linux/

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