Make using the "classic" edition of Ember throw

(cherry picked from commit 47f3381)

lib/index.js

@@ -112,27 +112,9 @@ module.exports = {
         throw new SilentError(message.join('\n\t'));
       }
     } else {
-      this.ui.writeWarnLine(
-        'The Ember Classic edition has been deprecated. Specifying "classic" in your package.json, or not specifying a value at all, will no longer be supported. You must explicitly set the "ember.edition" property to "octane". This warning will become an error in Ember 4.0.0.\n\nFor more information, see the deprecation guide: https://deprecations.emberjs.com/v3.x/#toc_editions-classic'
+      throw new SilentError(
+        'The Ember Classic edition has been removed. Specifying "classic" in your package.json, or not specifying a value at all, is no longer supported. You must explicitly set the "ember.edition" property to "octane". You can also run `npx @ember/octanify` to do this. \n\nFor more information, see the deprecation guide: https://deprecations.emberjs.com/v3.x/#toc_editions-classic'
       );
-
-      if (
-        optionalFeaturesMissing ||
-        optionalFeatures.isFeatureEnabled('application-template-wrapper')
-      ) {
-        this.ui.writeWarnLine(
-          'Setting the `application-template-wrapper` optional feature flag to `true`, or not providing a setting at all, has been deprecated. You must add the `@ember/optional-features` addon and set this feature to `false`. You can also run `npx @ember/octanify` to do this. This warning will become an error in Ember 4.0.0.\n\nFor more information, see the deprecation guide: https://deprecations.emberjs.com/v3.x/#toc_optional-feature-application-template-wrapper'
-        );
-      }
-
-      if (
-        optionalFeaturesMissing ||
-        !optionalFeatures.isFeatureEnabled('template-only-glimmer-components')
-      ) {
-        throw new SilentError(
-          'Setting the `template-only-glimmer-components` optional feature flag to `false`, or not providing a setting at all, was deprecated in Ember 3.x and removed in Ember 4.0.0. You must add the `@ember/optional-features` addon and set this feature to `true`.\n\nFor more information, see the deprecation guide: https://deprecations.emberjs.com/v3.x/#toc_optional-feature-template-only-glimmer-components'
-        );
-      }
     }
 
     if (