fix GB2 student cell layout when 'hide student names' is checked

fixes CNVS-10359

test plan:
- in GB2, select 'Hide Studend Names' from the cog menu
- the student name column should look good

Change-Id: I4b4d0eeddcbca6880f8ca7494606cbc3c06874d9
Reviewed-on: https://gerrit.instructure.com/28306
Tested-by: Jenkins <jenkins@instructure.com>
QA-Review: Caleb Guanzon <cguanzon@instructure.com>
Reviewed-by: Matthew Irish <mirish@instructure.com>
Product-Review: Simon Williams <simon@instructure.com>