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/is-number/index.js

@@ -0,0 +1,18 @@
+/*!
+ * is-number <https://github.com/jonschlinkert/is-number>
+ *
+ * Copyright (c) 2014-present, Jon Schlinkert.
+ * Released under the MIT License.
+ */
+
+'use strict';
+
+module.exports = function(num) {
+  if (typeof num === 'number') {
+    return num - num === 0;
+  }
+  if (typeof num === 'string' && num.trim() !== '') {
+    return Number.isFinite ? Number.isFinite(+num) : isFinite(+num);
+  }
+  return false;
+};