Change "topics" to "topic" in contest queries

[rbennettcw]

After making contest topics one-to-one, there are still some queries that return an array of topics (with a guaranteed length of 0 or 1). The queries should be cleaned up so that it returns the topic object instead of an array. Currently the getAllContests query is the only known affected query, but others may exist too.

Acceptance Criteria

• Any contest queries that return an array of topics per contest manager should only return the single topic, not array. Rename topics to topic
• The UI should be updated accordingly