fixes CNVS-8836
test plan:
- create a formula question
- add a question where the answer will be negative
- add a percentage margin of error
- make sure adding an answer above/below that margin of error works correctly
Change-Id: I80ed024d0a83109f006563145bc2f363bb25418f
Reviewed-on: https://gerrit.instructure.com/25304
Tested-by: Jenkins <jenkins@instructure.com>
QA-Review: Myller de Araujo <myller@instructure.com>
Reviewed-by: Josh Simpson <jsimpson@instructure.com>
Product-Review: Derek DeVries <ddevries@instructure.com>