remove unused config option

especially since we don't use dynamic finders anymore

refs CNVS-15126

Change-Id: Idba2142a8b4559ddf7932e5f155d4744f30c7c19
Reviewed-on: https://gerrit.instructure.com/41280
Reviewed-by: Brian Palmer <brianp@instructure.com>
Tested-by: Jenkins <jenkins@instructure.com>
Product-Review: Cody Cutrer <cody@instructure.com>
QA-Review: Cody Cutrer <cody@instructure.com>