update nb-x-k12 translation
update nb-x-k12 translation

Change-Id: I28d0b325fc36bb00e4685b2477b59cfcbcfebede
Reviewed-on: https://gerrit.instructure.com/c/canvas-lms/+/303889
Tested-by: Service Cloud Jenkins <9144042a601061f88f1e1d7a1753ea3e2972119d@instructure.com>

instructure/canvas-lms,instructure/canvas-lms,instructure/canvas-lms,instructure/canvas-lms,instructure/canvas-lms,instructure/canvas-lms,instructure/canvas-lms