Fixed Issues for On-Premises Appliance Version 121.0.0

The following fixed issues are included in this release.

Issue Number	Issue	Description
476993	Publishing metrics from the Appliance platform could be disabled.	Fixed.
503376	Netmask notation is supported in the ssh-allowlist.	Fixed.
540238	The High Availability (HA) status for Appliance was not visible on the CLI or via the SNMP.	Fixed.