DA - hide feature flag from prod

Change-Id: I2dc37127e6050bb8aaacec900effa784e445fdb3
Reviewed-on: https://gerrit.instructure.com/44013
Reviewed-by: Cameron Sutter <csutter@instructure.com>
Tested-by: Jenkins <jenkins@instructure.com>
Product-Review: Matt Fairbourn <mfairbourn@instructure.com>
QA-Review: Matt Fairbourn <mfairbourn@instructure.com>