### 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
ERR_FAIL_COND(edited_theme.is_null());
	if (updating) {
		return;
	}
	updating = true;
	Control *focused = get_viewport()->gui_get_focus_owner();
	if (focused) {
		if (focusables.has(focused)) {
			
			updating = false;
			return;
		}
		Node *focus_parent = focused->get_parent();
		while (focus_parent) {
			Control *c = Object::cast_to<Control>(focus_parent);
			if (c && focusables.has(c)) {
				
				updating = false;
				return;
			}
			focus_parent = focus_parent->get_parent();
		}
	}
	List<StringName> theme_types;
	edited_theme->get_type_list(&theme_types);
	theme_types.sort_custom<StringName::AlphCompare>();
	theme_type_list->clear();
	if (theme_types.size() > 0) {
		theme_type_list->set_disabled(false);
		bool item_reselected = false;