[ubports/24.04-1.x] PushClient: migrate to ClearPersistentList DBus call
Backport: !10 (merged)
Newer version of lomiri-push-service are no longer able to understand "variadic argument" technique used previously, so now ClearPersistent can accept only 1 tag per call.
Switch to new ClearPersistentList which accepts an array of tags instead. This requires updated version of lomiri-push-service; since we're a system component we can effort this.