I did not, I coded it from scratch. I wrote out the dialogue out in creately to develop the tree system/visualize the flow of dialogue (I used a flowchart template). Once I'd written the text and figured out what I wanted the characters to say, I coded a Heap which I stored the dialogue lines in, where each node's children were response(s) to a given line of dialogue. Outside of the structure I tracked whose turn it was to speak so I could just pull the top lines and put them in the right spot. I then had to put all the dialogue in by hand, adding each node to the heap manually. Not the best system, I know, but I thought about it for awhile and given the time crunch this felt the most feasible. The text effects that you then see (expanding dialogue box, colored/live typing, rich text) were all coded from scratch as well, using Unity's TextMeshPro. They were actually not too hard once I found the right part of the TMPro documentation, and are decently modular.
I've never made a dialogue system on this scale before, and given the time constraints I definitely had to cut some corners to make it work, so not the greatest code. In the future I would probably use an external dialogue system asset, or spend more time and really develop my own dialogue system that would be more modular and expandable.