### Godot version

v4.0.beta.custom_build [eaf306e0b]

### System information

Windows 10

### Issue description

Selecting a `Window` node in the Editor's SceneTree results in the message
```
editor/editor_data.cpp:1058 - Parameter "p_node" is null.
```
and the Inspector shows empty content instead of the Window's properties.

I would expect, that clicking on a node in the SceneTree lets me edit the properties of the node.

Bisecting shows that this behavior got introduced in #71770

### Steps to reproduce

1. Create a Window node
2. Click on the Window node in the Editor's SceneTree

### Minimal reproduction project

N/A
TreeItem *child_item = p_root_item->get_first_child();
	while (child_item) {
		child_item->set_checked(IMPORT_ITEM, true);
		if (p_select_with_data) {
			child_item->set_checked(IMPORT_ITEM_DATA, true);
		}
		_store_selected_item(child_item);
		_select_all_subitems(child_item, p_select_with_data);
		child_item = child_item->get_next();
	}
}
void ThemeItemImportTree::_deselect_all_subitems(TreeItem *p_root_item, bool p_deselect_completely) {
	TreeItem *child_item = p_root_item->get_first_child();
	while (child_item) {
		child_item->set_checked(IMPORT_ITEM_DATA, false);
		if (p_deselect_completely) {
			child_item->set_checked(IMPORT_ITEM, false);
		}
		_store_selected_item(child_item);
		_deselect_all_subitems(child_item, p_deselect_completely);
		child_item = child_item->get_next();
	}
}
void ThemeItemImportTree::_select_all_items_pressed() {