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/proposals/array-unique.js

@@ -0,0 +1,5 @@
+'use strict';
+// https://github.com/tc39/proposal-array-unique
+require('../modules/es.map');
+require('../modules/esnext.array.unique-by');
+require('../modules/esnext.typed-array.unique-by');