In react-beautiful-dnd example focused input don't swap

### Are you submitting a **bug report** or a **feature request**?
Bug

### What is the current behavior?
In react-beautiful-dnd example if few items created and one of inputs get focused and then dragged the it gets blurred and the swapped item get focused

1. create two items(or more) in react-beautiful-dnd example
2. choose one of the items and focus one of it's inputs
3. swap(drag) it with other item
### What is the expected behavior?
dragged item persist focus
### Sandbox Link
[https://codesandbox.io/s/678pj?file=/index.js](https://codesandbox.io/s/678pj?file=/index.js)

### What's your environment?

```"final-form": "^4.18.7",
"final-form-arrays": "^3.0.2",
"react-final-form": "^6.3.5",
"react-final-form-arrays": "^3.1.2",
"react-beautiful-dnd": "^13.0.0",
"react": "^16.13.0",
"react": "^16.13.0",
```
### Other information

Start with the react-beautiful-dnd example and reproduce the behavior using the linked CodeSandbox: create multiple items, focus an input, and drag it to swap positions. Trace the example's focus behavior during reordering; done means the dragged item's input remains focused after the swap.

Written by the indexing model from the issue text.