Currently if there is IllegalArgumentException thrown from http handler, the HttpExceptionHandler will turn it into a 500 response, but I think 400 should be returned instead.
Yes, please. It is annoying for each handler to individually catch it and respond with 400.
Or to catch a JsonSyntaxException and throw a 400.
Part of this PR could have been unnecessary if this Jira was implemented: https://github.com/caskdata/cdap/pull/10540