To answer this question succinctly: not often.
And for this case in John which you've cited it is not endemic to the oldest available manuscripts. I am not aware of any excerpt from the oldest manuscripts which has stylistic formatting (and I do not know the whole manuscripts from beginning to end). As for what I've seen, the style is consistently clear-cut.
The manuscripts of the New Testament and its contemporary Greek texts are almost universally pragmatic in their function for a reason. Substance is emphasized over style because the ultimate objective of scriptural manuscripts was to preserve and multiply the accounts as expediently as possible.
If you observe 1 John as preserved in the Sinaiticus to give an example, you will notice that verses 12-14 are divided between two separate paragraphical bodies. There is no indication in the Greek for a formatting as seen in your chosen translation. Many passages of the New Testament are presented as you have noted solely due to the discretion of the translator or publisher. It is simply aesthetic and placed into publications for ease of reading or to insert a literary device. If you explore the above link to the Sinaiticus, you will see that it is quite uniform from beginning to end. The Vaticanus and Alexandrinus are comparable, etc.
We must also remember that Koine Greek grammar functions much differently than written English and wouldn't always faire under modern tropes as we might imagine it anyways. This kind of translation (as simple as it is) wouldn't be a basic copy and paste even if it were to appear. Just to bring some things to mind: nouns being identified by substantives, the absence of punctuational marks, and other matters make Greek texts much more clear cut than one would realize if only gleaning upon a respective English translation.
Substance over style is the name of the game.
I want to make an additional point which is important: we must always remember to not read a translator's discretion as being indicative of the original author's intent. You therefore did a good thing in asking this question. Not everyone asks it. Translation is in large part interpretation, and decisions of choice long ago resulted in differences between manuscripts. Today, biases and opinions over the meaning of words result in translational errors. Scribal interjection is in no way a modern contrivance, and as workmen we must not take anything for granted and always bring ourselves as close to the original as we can manage.