Removed unused react examples folder

Change-Id: Id6a0040ad28ed915266bb5c64f859b69a5b3f5c5
Reviewed-on: https://gerrit.instructure.com/45337
Product-Review: Colleen Palmer <colleen@instructure.com>
Reviewed-by: Colleen Palmer <colleen@instructure.com>
Tested-by: Jenkins <jenkins@instructure.com>
QA-Review: Eric Berry <ericb@instructure.com>