fix fragile srgb global settings spec

fixes CNVS-10730

test plan:
 - specs should pass

Change-Id: I8c490d1aa8e6ef88470ddfc66c8423f232ab78cc
Reviewed-on: https://gerrit.instructure.com/29143
Tested-by: Bryan Madsen <bryan@instructure.com>
Reviewed-by: Bryan Madsen <bryan@instructure.com>
QA-Review: Bryan Madsen <bryan@instructure.com>
Product-Review: Bryan Madsen <bryan@instructure.com>