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.array.join.js

@@ -0,0 +1,19 @@
+'use strict';
+var $ = require('../internals/export');
+var uncurryThis = require('../internals/function-uncurry-this');
+var IndexedObject = require('../internals/indexed-object');
+var toIndexedObject = require('../internals/to-indexed-object');
+var arrayMethodIsStrict = require('../internals/array-method-is-strict');
+
+var nativeJoin = uncurryThis([].join);
+
+var ES3_STRINGS = IndexedObject !== Object;
+var FORCED = ES3_STRINGS || !arrayMethodIsStrict('join', ',');
+
+// `Array.prototype.join` method
+// https://tc39.es/ecma262/#sec-array.prototype.join
+$({ target: 'Array', proto: true, forced: FORCED }, {
+  join: function join(separator) {
+    return nativeJoin(toIndexedObject(this), separator === undefined ? ',' : separator);
+  }
+});