update en-GB translation
update en-GB translation

Change-Id: Ie419792591de4051aec362c8fb05ea073d8660ae

venturehive/canvas-lms,grahamb/canvas-lms,HotChalk/canvas-lms,SwinburneOnline/canvas-lms,SwinburneOnline/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,djbender/canvas-lms,sfu/canvas-lms,grahamb/canvas-lms,sfu/canvas-lms,HotChalk/canvas-lms,grahamb/canvas-lms,fronteerio/canvas-lms,sfu/canvas-lms,roxolan/canvas-lms,HotChalk/canvas-lms,fronteerio/canvas-lms,djbender/canvas-lms,SwinburneOnline/canvas-lms,fronteerio/canvas-lms,sfu/canvas-lms,roxolan/canvas-lms,djbender/canvas-lms,roxolan/canvas-lms,SwinburneOnline/canvas-lms,djbender/canvas-lms,grahamb/canvas-lms,grahamb/canvas-lms,roxolan/canvas-lms,venturehive/canvas-lms,sfu/canvas-lms,HotChalk/canvas-lms,fronteerio/canvas-lms,venturehive/canvas-lms,venturehive/canvas-lms