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/string-trim-end.js

@@ -0,0 +1,11 @@
+'use strict';
+var $trimEnd = require('../internals/string-trim').end;
+var forcedStringTrimMethod = require('../internals/string-trim-forced');
+
+// `String.prototype.{ trimEnd, trimRight }` method
+// https://tc39.es/ecma262/#sec-string.prototype.trimend
+// https://tc39.es/ecma262/#String.prototype.trimright
+module.exports = forcedStringTrimMethod('trimEnd') ? function trimEnd() {
+  return $trimEnd(this);
+// eslint-disable-next-line es/no-string-prototype-trimstart-trimend -- safe
+} : ''.trimEnd;