use proper shell escaping for qti converter
use proper shell escaping for qti converter

test plan: sanity check course copy/export/import
           and QTI .zip import

fixes CNVS-29108

Change-Id: Ia233daeb63a54a6ce66395114d0e400fa7943571
Reviewed-on: https://gerrit.instructure.com/78544
Reviewed-by: James Williams  <3a5f4ed991dbfa5c9ef76ad729d240ca12f62180@instructure.com>
QA-Review: Jahnavi Yetukuri <ed2b2672ccc2e59e56c0615df7f01b579202e014@instructure.com>
Tested-by: Jenkins
Product-Review: Jeremy Stanley <b3f594e10a9edcf5413cf1190121d45078c62290@instructure.com>

dgynn/canvas-lms,SwinburneOnline/canvas-lms,instructure/canvas-lms,sfu/canvas-lms,dgynn/canvas-lms,venturehive/canvas-lms,fronteerio/canvas-lms,matematikk-mooc/canvas-lms,grahamb/canvas-lms,venturehive/canvas-lms,venturehive/canvas-lms,instructure/canvas-lms,grahamb/canvas-lms,HotChalk/canvas-lms,fronteerio/canvas-lms,HotChalk/canvas-lms,djbender/canvas-lms,dgynn/canvas-lms,sfu/canvas-lms,instructure/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,grahamb/canvas-lms,djbender/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,dgynn/canvas-lms,instructure/canvas-lms,djbender/canvas-lms,sfu/canvas-lms,venturehive/canvas-lms,matematikk-mooc/canvas-lms,SwinburneOnline/canvas-lms,matematikk-mooc/canvas-lms,SwinburneOnline/canvas-lms,SwinburneOnline/canvas-lms,fronteerio/canvas-lms,HotChalk/canvas-lms,grahamb/canvas-lms,fronteerio/canvas-lms,grahamb/canvas-lms,HotChalk/canvas-lms,matematikk-mooc/canvas-lms,instructure/canvas-lms,instructure/canvas-lms,djbender/canvas-lms,instructure/canvas-lms