Fix ResizeFormListener using integer keys

[franmomu]

Subject

Ref sonata-project/SonataDoctrineMongoDBAdminBundle#699

In Symfony 6, Form::add method accepts FormInterface|string as first parameter.

When using CollectionType, the data is an array with integer keys and the FormResizerListener is using these keys to call Form:add.

form-extensions/src/EventListener/ResizeFormListener.php

Lines 101 to 109 in 7b5f2b7

	// Then add all rows again in the correct order
	foreach ($data as $name => $value) {
	$options = array_merge($this->typeOptions, [
	'property_path' => '['.$name.']',
	'data' => $value,
	]);
	$form->add($name, $this->type, $options);
	}

which means that it throws a TypeError.

I am targeting this branch, because this is BC.

Changelog

### Fixed
- Using `CollectionType` with Symfony 6

[jordisala1991]

Thanks