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

Change-Id: If50f92bf941af4da00378802e89a8829c735fc1f
Reviewed-on: https://gerrit.instructure.com/c/canvas-lms/+/264635
Tested-by: Service Cloud Jenkins <9144042a601061f88f1e1d7a1753ea3e2972119d@instructure.com>

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