still convert \n to NewlinePart when pasting/dropping
before we skipped the complete validation (which creates NewlineParts)
when pasting or dropping text. We don't want to create PillCandidatePart
when inserting text like this, as it would open the auto-complete, but
newlines should still be applied. So instead of skipping validation,
pass the inputType to the validation code so they can only reject
pill candidate characters when not pasting.