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/whatwg-url/lib/utils.js

@@ -0,0 +1,20 @@
+"use strict";
+
+module.exports.mixin = function mixin(target, source) {
+  const keys = Object.getOwnPropertyNames(source);
+  for (let i = 0; i < keys.length; ++i) {
+    Object.defineProperty(target, keys[i], Object.getOwnPropertyDescriptor(source, keys[i]));
+  }
+};
+
+module.exports.wrapperSymbol = Symbol("wrapper");
+module.exports.implSymbol = Symbol("impl");
+
+module.exports.wrapperForImpl = function (impl) {
+  return impl[module.exports.wrapperSymbol];
+};
+
+module.exports.implForWrapper = function (wrapper) {
+  return wrapper[module.exports.implSymbol];
+};
+