[i18n] update english locale with new strings
[i18n] update english locale with new strings

Change-Id: Ia101aff16f084c5ea286cdd85ed271fc0ee07fd4
Reviewed-on: https://gerrit.instructure.com/116393
Tested-by: Jenkins

instructure/canvas-planner,instructure/canvas-planner,instructure/canvas-planner