set answer text to identifier for bb learn true/false questions

test plan:
* import the package referenced in the ticket
* should not import the wrong answer text for the questions

fixes #CNVS-9381 frd

Change-Id: I42e125c64bf5009b4384d7cc18edf75d7bcfc9f1
Reviewed-on: https://gerrit.instructure.com/30164
Reviewed-by: Bracken Mosbacker <bracken@instructure.com>
Product-Review: Bracken Mosbacker <bracken@instructure.com>
Tested-by: Jenkins <jenkins@instructure.com>
QA-Review: Matt Fairbourn <mfairbourn@instructure.com>