[BUGFIX release] revert deprecation of htmlSafe and isHTMLSafe

packages/ember/index.js

@@ -449,7 +449,14 @@ Ember.String = {
   classify,
   underscore,
   capitalize,
+  htmlSafe,
+  isHTMLSafe,
 };
+if (ENV.EXTEND_PROTOTYPES.String) {
+  String.prototype.htmlSafe = function () {
+    return htmlSafe(this);
+  };
+}
 Ember.Object = EmberObject;
 Ember._RegistryProxyMixin = RegistryProxyMixin;
 Ember._ContainerProxyMixin = ContainerProxyMixin;
@@ -652,42 +659,6 @@ if (EMBER_GLIMMER_INVOKE_HELPER) {
 }
 Ember._captureRenderTree = captureRenderTree;
 
-if (ENV.EXTEND_PROTOTYPES.String) {
-  String.prototype.htmlSafe = function () {
-    return htmlSafe(this);
-  };
-}
-const deprecateImportFromString = function (
-  name,
-  message = `Importing ${name} from '@ember/string' is deprecated. Please import ${name} from '@ember/template' instead.`
-) {
-  deprecate(message, false, {
-    id: 'ember-string.htmlsafe-ishtmlsafe',
-    for: 'ember-source',
-    since: {
-      enabled: '3.25',
-    },
-    until: '4.0.0',
-    url: 'https://deprecations.emberjs.com/v3.x/#toc_ember-string-htmlsafe-ishtmlsafe',
-  });
-};
-Object.defineProperty(Ember.String, 'htmlSafe', {
-  enumerable: true,
-  configurable: true,
-  get() {
-    deprecateImportFromString('htmlSafe');
-    return htmlSafe;
-  },
-});
-Object.defineProperty(Ember.String, 'isHTMLSafe', {
-  enumerable: true,
-  configurable: true,
-  get() {
-    deprecateImportFromString('isHTMLSafe');
-    return isHTMLSafe;
-  },
-});
-
 /**
   Global hash of shared templates. This will automatically be populated
   by the build tools so that you can store your Handlebars templates in