Fix <SimpleList> always returns empty when controlled

[fzaninotto]

<SimpleList data={data}> always renders an empty list regardless of the data.

Test the ra-ui-material-ui/list/simplelist/basic story to see the bug.

Cause

Even when the data prop is set, this condition forces the rendering of the empty component because total is also undefined.

react-admin/packages/ra-ui-materialui/src/list/SimpleList/SimpleList.tsx

Lines 123 to 129 in a402c38

	if (data == null || total == null || data.length === 0 || total === 0) {
	if (empty) {
	return empty;
	}
	return null;
	}

The condition is different in <Datagrid>:

react-admin/packages/ra-ui-materialui/src/list/datagrid/Datagrid.tsx

Lines 219 to 225 in a402c38

	if (data == null || data.length === 0 || total === 0) {
	if (empty) {
	return empty;
	}
	return null;
	}

Solution

Remove the test on total in <SimpleList> empty clause