Write an upgrader to add hidden schema fields to all remaining schemas with undeclared fields

To finish #5302, we need to have an upgrader which adjusts existing schemas for markers with undeclared fields. For example, if a field is mentioned in the tooltipLabel, or if it is used by a marker-based graph, it needs to be added to the schema and declared as hidden. (The ability to declare fields as hidden is #5299.)

I'm not sure whether this should be done in a generic fashion, or only for the marker types found in #5281.

┆Issue is synchronized with this [Jira Task](https://mozilla-hub.atlassian.net/browse/FP-857)