update en-GB translation
update en-GB translation

Change-Id: I56a57d1691ee9e3d5d928f6e676be20c0703132f

djbender/canvas-lms,sfu/canvas-lms,HotChalk/canvas-lms,grahamb/canvas-lms,sfu/canvas-lms,matematikk-mooc/canvas-lms,SwinburneOnline/canvas-lms,instructure/canvas-lms,SwinburneOnline/canvas-lms,venturehive/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,SwinburneOnline/canvas-lms,djbender/canvas-lms,instructure/canvas-lms,instructure/canvas-lms,instructure/canvas-lms,HotChalk/canvas-lms,venturehive/canvas-lms,HotChalk/canvas-lms,djbender/canvas-lms,HotChalk/canvas-lms,grahamb/canvas-lms,instructure/canvas-lms,grahamb/canvas-lms,djbender/canvas-lms,grahamb/canvas-lms,instructure/canvas-lms,venturehive/canvas-lms,matematikk-mooc/canvas-lms,sfu/canvas-lms,venturehive/canvas-lms,grahamb/canvas-lms,matematikk-mooc/canvas-lms,instructure/canvas-lms,matematikk-mooc/canvas-lms,SwinburneOnline/canvas-lms,sfu/canvas-lms