FRE-600: Fix code review blockers

- Consolidated duplicate UndoManagers to single instance
- Fixed connection promise to only resolve on 'connected' status
- Fixed WebSocketProvider import (WebsocketProvider)
- Added proper doc.destroy() cleanup
- Renamed isPresenceInitialized property to avoid conflict

Co-Authored-By: Paperclip <noreply@paperclip.ing>

node_modules/core-js/internals/create-non-enumerable-property.js

@@ -0,0 +1,11 @@
+'use strict';
+var DESCRIPTORS = require('../internals/descriptors');
+var definePropertyModule = require('../internals/object-define-property');
+var createPropertyDescriptor = require('../internals/create-property-descriptor');
+
+module.exports = DESCRIPTORS ? function (object, key, value) {
+  return definePropertyModule.f(object, key, createPropertyDescriptor(1, value));
+} : function (object, key, value) {
+  object[key] = value;
+  return object;
+};