message: fix(browser): Make sure handler exists for LinkedErrors Integration
  We should port the fixes done in the Node SDK in
  to the browser
  SDK.
  This makes sure that the handler class method is defined in the linked
  errors integration.
diff: @@ -45,7 +45,8 @@ export class LinkedErrors implements Integration {
  addGlobalEventProcessor((event: Event, hint?: EventHint) => {
  const self = getCurrentHub().getIntegration(LinkedErrors);
  if (self) {
  - return self._handler(event, hint);
  + const handler = self._handler && self._handler.bind(self);
  + return typeof handler === 'function' ? handler(event, hint) : event;
  }
  return event;
  });
  