This diff does two things:
- Adds logging in checkInputValidator so we know what input validator is being failed.
- Makes sure that we don't throw a different error if sanitizeInput fails due to input validation. Instead, we'll just not include the sanitizedInput in the error.
(On the second point, I'm not entirely sure if it's ever possible for sanitizeInput to succeed input validation if it fails earlier...)
Depends on D12386