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/internals/a-number.js

@@ -0,0 +1,7 @@
+'use strict';
+var $TypeError = TypeError;
+
+module.exports = function (argument) {
+  if (typeof argument == 'number') return argument;
+  throw new $TypeError('Argument is not a number');
+};