Kudos emails sometimes contain the same name twice
Description
What happens
Occasionally, you'll get a kudos email that says, "UserA, UserA, and UserB left kudos on Title."
When you go to the work in question and check the kudos section, UserA's name only appears on the list once. A look at the database confirms the kudos is only recorded once. This is correct – users are only supposed to be able to leave kudos once per work.
What should happen
Names should only be in the kudos email once.
Notes
We've been seeing a bunch of KudosController#create ActiveRecord::Deadlocked errors in New Relic that end with the transaction being aborted. Could this possibly be related?
