fix: make the library compatible with React 19

[Danchoys]

Why is it needed

Library crashes instantly when someone presses on a filter to open the dropdown with possible values with a "t.findDOMNode is not a function" error.

Why is it happening

react-pivottable is using an older version of react-draggable library that uses a currently deprecated API from React: ReactDOM.findDOMNode.

What is changed

• react-draggable upgraded to @^4.5.0
• Added the necessary nodeRef and ref props as per react-draggable docs
• Added the prepare script to be able to install it from my fork :)