* DEV: upgrade grant badge modal to glimmer
* DEV: add unit tests for grant badge utils
* DEV: replace grant-badge-controller mixin with grant-badge-utils in admin-user-badges controller
* DEV: remove GrantBadgeController mixin
Moving the `grantBadge` action out of the actions hash caused it to clash with a method of the same name from the GrantBadgeController mixin. This commit renames the action.