spec: fix sub-second dependency in quiz spec

refs CNVS-7032

Change-Id: Iff4a96c3da6119782780c6bdab367342296e6b21
Reviewed-on: https://gerrit.instructure.com/29056
Reviewed-by: Cody Cutrer <cody@instructure.com>
Tested-by: Jenkins <jenkins@instructure.com>
Product-Review: Cody Cutrer <cody@instructure.com>
QA-Review: Cody Cutrer <cody@instructure.com>