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/to-big-int.js

@@ -0,0 +1,13 @@
+'use strict';
+var toPrimitive = require('../internals/to-primitive');
+
+var $TypeError = TypeError;
+
+// `ToBigInt` abstract operation
+// https://tc39.es/ecma262/#sec-tobigint
+module.exports = function (argument) {
+  var prim = toPrimitive(argument, 'number');
+  if (typeof prim == 'number') throw new $TypeError("Can't convert number to bigint");
+  // eslint-disable-next-line es/no-bigint -- safe
+  return BigInt(prim);
+};