Don't include private-address in the default Scenario database when mocking Juju 4 #2185
Description
The private-address key is not included in the default relation settings (databag) as of Juju 4.0, so we should not include it in the mock one either, if the mock Juju version is 4.0+.
The default contents are currently set when a Relation (etc) object is created. We don't have access to the relevant Context object at that time (which is where the Juju version is), so we'll have to figure out what the best way of handling this is.