fixing grammar on options toggle

test plan:
  go to course settings page and hit edit course details
  the options toggle should say "fewer options" once clicked
  the toggle should work as expected

changed "less options" to "fewer options"

Change-Id: I4b82120339b502c9a1b06875cfed1b7cd6993cb6
Reviewed-on: https://gerrit.instructure.com/29793
Reviewed-by: Cameron Sutter <csutter@instructure.com>
Tested-by: Jenkins <jenkins@instructure.com>
QA-Review: Caleb Guanzon <cguanzon@instructure.com>
Product-Review: Mike Nomitch <mnomitch@instructure.com>