Issue Summary

When a JSON file (which gives a parsing error) is used to create an import source, not all data source fields are populated. Expectation is that all selectors should be visible in the dropdown, but that is not happening in the new architecture.

Steps to Reproduce

1. Create a JSON Import with a large json file (a NDJSON format - new line delimited json )
   1. Note: a new line delimited json is a json which gives a parsing error, because there are json elements separated by new lines. An example file is attached here

1. Enable auto schema creation, and create import
2. Check any import source OT in mapping, which has nested json keys (Properties in this example file)
3. look for the data source field amongst the the leaf json keys (Tags in this example file)

Expected Results

All data source fields should be visible, as they are visible in old architecture

Actual Results

Only the data source fields corresponding to the first element in the JSON file are populated.
In this example these tags are only present in the first element of the JSON file

Workaround

If the NDJSON file is converted into a normal JSON, which can be parsed - the behaviour is fixed.

invalid JSON:

{...element1...}
{...element2...}
{...element3...} 

Correctly formatted JSON:

[
  {...element1...},
  {...element2...},
  {...element3...}
]