`registerUnbound` was present for legacy reasons when using helpers in raw-hbs and has been replaced by `registerRawHelper`.
For new helpers used only in classic ember template, exporting a default function from `helpers/*.js` is recommended.
This change also means that all existing helpers will be available to import in `gjs` files.
Co-authored-by: David Taylor <david@taylorhq.com>
As of #23867 this is now a real package, so updating the imports to
use the real package name, rather than relying on the alias. The
name change in the package name is because `I18n` is not a valid
name as NPM packages must be all lowercase.
This commit also introduces an eslint rule to prevent importing from
the old I18n path.
For themes/plugins, the old 'i18n' name remains functional.
