[bug] Class instances are getting replaced by plain JS objects

[IAmJulianAcosta]

Describe the bug
Class instances are getting replaced by plain JS objects

To Reproduce
Steps to reproduce the behavior:

• Use class instances as items
• Try to reproduce them
• The instances are now plain objects

Expected behavior
When sorting a list that has class instances as items, the instances should remain as is, not changed to generic JS objects

Information
This is required. Issues without this critical information will be closed.

Versions - Look in your package.json for this information:
react-sortable = ^6.0.3
react = ^17.0.2

Additional context
Add any other context about the problem here.

Please provide examples, screenshots or a code sandbox for faster resolution times.
Clone and run https://github.com/IAmJulianAcosta/react-sortablejs-error-demo