fix i18n import issues around wrapper validation, fixes CNVS-17482

handle nesting and extraneous whitespace

test plan:
1. specs should pass
2. latest strings should not give a wrapper error around
   discrimination_index_help

Change-Id: I553395830f9a219ccc7c6f3ff580dab05c065fbc
Reviewed-on: https://gerrit.instructure.com/45721
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Addison Higham <ahigham@instructure.com>
Product-Review: Jon Jensen <jon@instructure.com>
QA-Review: Jon Jensen <jon@instructure.com>