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

Change-Id: I8a0cf8ffdd81e075e88f64931275cc5c83b40d08
Reviewed-on: https://gerrit.instructure.com/135034
Tested-by: Jenkins

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