Setting juju config "nagios_check_pacemaker" to false don't remove Nagios checks

[Mathew Clarke]

If you enable "nagios_check_pacemaker" to true on an infra-node charm version 3 on focal that isn't running pacemaker/corosync and then set it to false, then the charm fails to remove the Nagios entries. Examples below

Host: <hostname>
Service: <hostname>-corosync_proc
Status: CRITICAL
Last check: 2023-02-17 09:37:58
Duration: 0d 0h 10m 52s
Attempt: 4/4
Status information: PROCS CRITICAL: 0 processes with command name 'corosync'

Host: <hostname>
Service: <hostname>-corosync_rings
Status: CRITICAL
Last check: 2023-02-17 09:38:26
Duration: 0d 0h 16m 24s
Attempt: 4/4
Status information: check_cororings CRITICAL - Running corosync-cfgtool failed

Host: <hostname>
Service: <hostname>-crm_status
Status: CRITICAL
Last check: 2023-02-17 09:38:49
Duration: 0d 0h 16m 1s
Attempt: 4/4
Status information: check_crm CRITICAL - Running /usr/sbin/crm_mon -1 -r -f FAILED

Host: <hostname>
Service: <hostname>-pacemakerd_proc
Status: CRITICAL
Last check: 2023-02-17 09:39:12
Duration: 0d 0h 15m 38s
Attempt: 4/4
Status information: PROCS CRITICAL: 0 processes with command name 'pacemakerd'