Changes proposed in this Pull Request
This removes the useLocalize hook and the LocalizeProvider from the @automattic/composite-checkout package. Instead, it uses __ from @wordpress/i18n (which we were already using under the hood) and @automattic/react-i18n.
This is part of #42831
Testing instructions
This should not cause any changes. Load composite checkout and be sure the strings look ok (they will not be translated yet).
Unfortunately, no screenshots were provided by the developer.
