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/web.clear-immediate.js

@@ -0,0 +1,10 @@
+'use strict';
+var $ = require('../internals/export');
+var globalThis = require('../internals/global-this');
+var clearImmediate = require('../internals/task').clear;
+
+// `clearImmediate` method
+// http://w3c.github.io/setImmediate/#si-clearImmediate
+$({ global: true, bind: true, enumerable: true, forced: globalThis.clearImmediate !== clearImmediate }, {
+  clearImmediate: clearImmediate
+});