### 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
if (!p_node) {
		return;
	}
	if (Object::cast_to<Viewport>(p_node)) {
		return;
	}
	const CanvasItem *ci = Object::cast_to<CanvasItem>(p_node);
	for (int i = p_node->get_child_count() - 1; i >= 0; i--) {
		if (ci && !ci->is_set_as_top_level()) {
			_expand_encompassing_rect_using_children(r_rect, p_node->get_child(i), r_first, p_parent_xform * ci->get_transform(), p_canvas_xform);
		} else {
			const CanvasLayer *cl = Object::cast_to<CanvasLayer>(p_node);
			_expand_encompassing_rect_using_children(r_rect, p_node->get_child(i), r_first, Transform2D(), cl ? cl->get_transform() : p_canvas_xform);
		}
	}
	if (ci && ci->is_visible_in_tree() && (include_locked_nodes || !_is_node_locked(ci))) {
		Transform2D xform = p_canvas_xform;