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.set.intersection.v2.js

@@ -0,0 +1,18 @@
+'use strict';
+var $ = require('../internals/export');
+var fails = require('../internals/fails');
+var intersection = require('../internals/set-intersection');
+var setMethodAcceptSetLike = require('../internals/set-method-accept-set-like');
+
+var INCORRECT = !setMethodAcceptSetLike('intersection', function (result) {
+  return result.size === 2 && result.has(1) && result.has(2);
+}) || fails(function () {
+  // eslint-disable-next-line es/no-array-from, es/no-set, es/no-set-prototype-intersection -- testing
+  return String(Array.from(new Set([1, 2, 3]).intersection(new Set([3, 2])))) !== '3,2';
+});
+
+// `Set.prototype.intersection` method
+// https://tc39.es/ecma262/#sec-set.prototype.intersection
+$({ target: 'Set', proto: true, real: true, forced: INCORRECT }, {
+  intersection: intersection
+});