Change from let to const for consistency with other repos
Change from let to const for consistency with other repos

ciena-frost/ember-frost-core,ciena-frost/ember-frost-core,dafortin/ember-frost-core,EWhite613/ember-frost-core,EWhite613/ember-frost-core,dafortin/ember-frost-core,ciena-frost/ember-frost-core,EWhite613/ember-frost-core,dafortin/ember-frost-core