There are a lot of error codes aggregation can throw for parsing errors. For processors that set $source.config.pipeline, we should be able to treat these parsing errors as user errors.

In order to reduce risk, we should only treat these errors as user errors for processors that are starting 'fresh' i.e. not starting from a checkpoint.

context:

https://github.com/10gen/mongo/pull/31758/files#r1934776008