force calendar2_only account setting to true

fixes CNVS-12331

before you check out
- configure some accounts to not use calendar2
- configure some users to prefer calendar1

test plan
- ensure that everyone gets calendar2, all the time, even if they
 specifically checked a box saying they don't want to use it

Change-Id: Ibe1eb6b86ccc1c9489b166c138c87a288eb91ac1
Reviewed-on: https://gerrit.instructure.com/34339
Tested-by: Jenkins <jenkins@instructure.com>
QA-Review: Trevor deHaan <tdehaan@instructure.com>
Reviewed-by: Braden Anderson <banderson@instructure.com>
Product-Review: Joel Hough <joel@instructure.com>