Adjusts statistics translation keys

fixes CNVS-14933

test plan:
  - Make sure it works for Transifex

Change-Id: I6598e5dc5854fbcea70caf77f2373817e17e3494
Reviewed-on: https://gerrit.instructure.com/39583
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Jeremy Stanley <jeremy@instructure.com>
QA-Review: Clare Strong <clare@instructure.com>
Product-Review: Cosme Salazar <cosme@instructure.com>