A one-hit wonder is any artist who's had only one single reach the Top 40 of the Hot 100, and sometimes a few other exceptions. For example: Cassie or Kat Deluna.
I don't use Leona, but clearly a one-hit wonder she is not.
Well you kinda just answered your own question since a one-hit wonder only has one song that makes it to the top 40, collaboration or otherwise. Seeing as she has three songs that reached that height, no she will not be a one-hit wonder in the US.