Change what gets sent from TestStateUpdater

previously, we didn't have an easy way to detect if the incoming message is meant to update the table. I just used a catchall 'else' statement (https://github.com/andreastt/certtest/compare/dev?expand=1#diff-bd18e39766162af226a2d44b007eb649L112) and if it's a message we don't expect, I'd just log it (https://github.com/andreastt/certtest/compare/dev?expand=1#diff-bd18e39766162af226a2d44b007eb649L67). So by sending an "updateTest" event, we know that we can safely send the payload to our updateTest function, and ignore any message that we don't expect.