update en-GB translation
update en-GB translation

Change-Id: Iab15b2683f13f4e1f9b0436ced37d703c207ee3d
Reviewed-on: https://gerrit.instructure.com/c/canvas-lms/+/255438
Tested-by: Service Cloud Jenkins <9144042a601061f88f1e1d7a1753ea3e2972119d@instructure.com>

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