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.is-frozen.js

@@ -0,0 +1,21 @@
+'use strict';
+var $ = require('../internals/export');
+var fails = require('../internals/fails');
+var isObject = require('../internals/is-object');
+var classof = require('../internals/classof-raw');
+var ARRAY_BUFFER_NON_EXTENSIBLE = require('../internals/array-buffer-non-extensible');
+
+// eslint-disable-next-line es/no-object-isfrozen -- safe
+var $isFrozen = Object.isFrozen;
+
+var FORCED = ARRAY_BUFFER_NON_EXTENSIBLE || fails(function () { $isFrozen(1); });
+
+// `Object.isFrozen` method
+// https://tc39.es/ecma262/#sec-object.isfrozen
+$({ target: 'Object', stat: true, forced: FORCED }, {
+  isFrozen: function isFrozen(it) {
+    if (!isObject(it)) return true;
+    if (ARRAY_BUFFER_NON_EXTENSIBLE && classof(it) === 'ArrayBuffer') return true;
+    return $isFrozen ? $isFrozen(it) : false;
+  }
+});