ENH: Add jsonline output format in to_dict(), failing type checks

[yukitakah]

• closes ENH: adding jsonline output format #58123 (Replace xxxx with the GitHub issue number)
• Tests added and passed if fixing a bug or adding a new feature
• All code checks passed.
• Added type annotations to new arguments/methods/functions.
• Added an entry in the latest doc/source/whatsnew/vX.X.X.rst file if fixing a bug or adding a new feature.

I got stuck and this is incomplete. Maybe it's not a great thing to do returning string in to_dict() functions.

[Aloqeely]

Thanks for the contribution! As mentioned in the original issue, this is already doable with DataFrame.to_json(orient='records', lines=True), and DataFrame.to_dict should only be returning a dictionary value and not a string (hence the name), so it doesn't make sense to implement it here

[WillAyd]

I agree with @Aloqeely - this should already be implemented via .to_json so no reason to duplicate that here