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

Change-Id: Id3f8885994c1d6b34d731c1f8e297355e7d96684
Reviewed-on: https://gerrit.instructure.com/114044
Tested-by: Jenkins

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