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

Change-Id: I835dc82a762b436aa0c1775fba27cf89ff66265b
Reviewed-on: https://gerrit.instructure.com/135369
Tested-by: Jenkins

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