update en-GB translation
update en-GB translation

Change-Id: I2095336e1c4fbd0362f48fa98997bbe5d19844e1

venturehive/canvas-lms,djbender/canvas-lms,instructure/canvas-lms,djbender/canvas-lms,venturehive/canvas-lms,instructure/canvas-lms,instructure/canvas-lms,instructure/canvas-lms,instructure/canvas-lms,sfu/canvas-lms,venturehive/canvas-lms,sfu/canvas-lms,venturehive/canvas-lms,sfu/canvas-lms,djbender/canvas-lms,instructure/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,djbender/canvas-lms,sfu/canvas-lms,instructure/canvas-lms,sfu/canvas-lms