In https://gerrit.wikimedia.org/r/#/c/259182/ we made InvalidInputException loggable, because debugging certain errors was hard without logging these exceptions. However, there was a good reason for not logging these exceptions: they tend to be thrown in response to bad user input like https://www.mediawiki.org/wiki/Topic:Blah

I don't remember the specific circumstances that required us to log these exceptions, but the fact that we started logging them suggests there are cases where we throw them for invalid input that didn't come from the user. We should stop throwing InvalidInputExceptions in those cases, so that we can make them non-loggable again.