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/modules/es.object.define-setter.js

@@ -0,0 +1,17 @@
+'use strict';
+var $ = require('../internals/export');
+var DESCRIPTORS = require('../internals/descriptors');
+var FORCED = require('../internals/object-prototype-accessors-forced');
+var aCallable = require('../internals/a-callable');
+var toObject = require('../internals/to-object');
+var definePropertyModule = require('../internals/object-define-property');
+
+// `Object.prototype.__defineSetter__` method
+// https://tc39.es/ecma262/#sec-object.prototype.__defineSetter__
+if (DESCRIPTORS) {
+  $({ target: 'Object', proto: true, forced: FORCED }, {
+    __defineSetter__: function __defineSetter__(P, setter) {
+      definePropertyModule.f(toObject(this), P, { set: aCallable(setter), enumerable: true, configurable: true });
+    }
+  });
+}