Removing Maximum length for NDJSON row

What does this MR do and why?

Removing MAX_JSON_DOCUMENT_SIZE limit as it is no longer needed, and never was needed.

See #421433 (comment 1509044055) for details

Screenshots or screen recordings

n/a

Before	After

How to set up and validate locally

Project import should work as usual

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #421433 (closed)