Fix memory check script so it works in Debian Bullseye

3 jobs for upgrade-monitoring-to-bullseye in 13 minutes and 51 seconds (queued for 6 seconds)
Status Name Job ID Coverage
  Check Code
passed check-code #222681
docker

00:01:15

 
  Tests
passed compile-profiles #222682
docker

00:12:35

passed enc-test #222683

00:00:34