Fix usage of MAX_LINES_TO_BE_RENDERED

What does this MR do?

In diffs/store/utils.js should be updating the viewer property of file. Since collapsed is not being updated properly the line limit set in diffs/constants.js is being ignored.

This MR removes the frontend check entirely since it is not being used and sets up support for #219565 (closed)

Screenshots

N/A

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content