Fix Arrayinput multiple reset

[erwanMarmelab]

Problem

you can’t properly reset your form (with an ArrayInput) twice.

Solution

How To Test

1. Open https://react-admin-storybook.vercel.app/?path=/story/ra-ui-materialui-input-arrayinput--reset
2. Add an empty line
3. Click the reset button
4. Add an empty line
5. Click the reset button

or

1. Open https://react-admin-storybook.vercel.app/?path=/story/ra-ui-materialui-input-arrayinput--reset
2. Add an empty line
3. fill it
4. Click the reset button
5. Add an empty line
6. fill it
7. Click the reset button

Additional Checks

• The PR targets master for a bugfix or a documentation fix, or next for a feature
• The PR includes unit tests (if not possible, describe why)
• The PR includes one or several stories (if not possible, describe why)
• The documentation is up to date

[erwanMarmelab]

good for me 👍

[slax57]

Other than that, LGTM