Check bennett bot has done all required tech-support and bennett-admins responding

[rebkwok]

Occasionally bennett bot fails to respond to the magic tech-support keyword. In the past week or so it seems to have happened a bit more often. There's no obvious reason for it - replying in the thread with a second call has always been answered, and reposting the exact same message wording again has also worked - this implies that it's not an issue with the slack bolt matcher, but rather with the slack bolt app receiving the message altogether. Logging is not much help because we can only log the events that the slack bolt app receives.

Suggested solution is to add a checker that runs in another thread and periodically searches slack for messages than mention tech-support but do not have the 🆘 reaction, and does the reacting/reposting for any that it finds. (ditto for bennett-admins, because that presumably will encounter the same issue from time to time.

WIP branch check-bot-responders