refactor keeping multiple copies of a specific cache key into a helper class

Change-Id: I7fd54391837e70fcb21b16573e2eb73cf533eb03
Reviewed-on: https://gerrit.instructure.com/42490
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Jacob Fugal <jacob@instructure.com>
Product-Review: Cody Cutrer <cody@instructure.com>
QA-Review: Cody Cutrer <cody@instructure.com>