A user reported that there is no email generated for this comment.
https://github.com/openjdk/jdk/pull/14114#issuecomment-1562126987

It is caused by the initial /csr needed command.

Currently, when archiving a comment, mlbridgeBot would strip everything after the first command. This is bad.

I think we could use the same strategy in CommandExtractor#extractCommands to filter out commands.