update en-GB translation
update en-GB translation

Change-Id: Ieced1f4ded07da025a2dc20e273c304ca589262d

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