i had assumed thatvalidated config data against schema, if it existed.
instead, that patch silently munges data to match schema.
can we fix that please?
a) use config schema as a validation step (i.e., before we end up in ->save()) - if the data doesn't match the schema, validation error. make this easy for forms and config entities (we should be able to make this a default, so that where such a schema exists, the config entity code will use it before ->save()).
b) use config schema to enforce correct input post-validation. code that uses the config system directly without forms may pass us data that doesn't match the schema, and won't go through form validation. in that case, use the schema to reject invalid data, rather than silently munge data