### 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
Node *scene = EditorNode::get_singleton()->get_edited_scene();
	_find_canvas_items_at_pos(p_pos, scene, r_items);
	
	for (int i = 0; i < r_items.size(); i++) {
		Node *node = r_items[i].item;
		
		if (node && node != get_tree()->get_edited_scene_root()) {
			node = scene->get_deepest_editable_node(node);
		}
		CanvasItem *ci = Object::cast_to<CanvasItem>(node);
		if (!p_allow_locked) {
			
			while (node && node != scene->get_parent()) {
				CanvasItem *ci_tmp = Object::cast_to<CanvasItem>(node);
				if (ci_tmp && node->has_meta("_edit_group_")) {
					ci = ci_tmp;
				}
				node = node->get_parent();
			}
		}
		
		bool duplicate = false;
		for (int j = 0; j < i; j++) {
			if (r_items[j].item == ci) {
				duplicate = true;