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/esnext.math.radians.js

@@ -0,0 +1,12 @@
+'use strict';
+var $ = require('../internals/export');
+
+var DEG_PER_RAD = Math.PI / 180;
+
+// `Math.radians` method
+// https://rwaldron.github.io/proposal-math-extensions/
+$({ target: 'Math', stat: true, forced: true }, {
+  radians: function radians(degrees) {
+    return degrees * DEG_PER_RAD;
+  }
+});