Download snippets with LF line-endings by default

What does this MR do?

When a raw snippet is requested it returns it with LF line endings by default (this can be overridden by line_ending param).

Why was this MR needed?

Requested in #21240 (closed)

Does this MR meet the acceptance criteria?

• Changelog entry added
• Documentation created/updated
• API support added
• Tests
  • Added for this feature/bug
  • All builds are passing
• Conform by the merge request performance guides
• Conform by the style guides
• Branch has no merge conflicts with master (if it does - rebase it please)
• Squashed related commits together

What are the relevant issue numbers?

Fixes #21240 (closed)