### 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
item_editor->set_edited_resource(Ref<Resource>());
			}
			item_editor->connect("resource_selected", callable_mp(this, &ThemeTypeEditor::_edit_resource_item));
			item_editor->connect("resource_changed", callable_mp(this, &ThemeTypeEditor::_stylebox_item_changed).bind(leading_stylebox.item_name));
			stylebox_items_list->add_child(item_control);
			stylebox_items_list->add_child(memnew(HSeparator));
		}
		HashMap<StringName, bool> stylebox_items = _get_type_items(edited_type, &Theme::get_stylebox_list, show_default);
		for (const KeyValue<StringName, bool> &E : stylebox_items) {
			if (leading_stylebox.pinned && leading_stylebox.item_name == E.key) {
				continue;
			}
			HBoxContainer *item_control = _create_property_control(Theme::DATA_TYPE_STYLEBOX, E.key, E.value);
			EditorResourcePicker *item_editor = memnew(EditorResourcePicker);
			item_editor->set_h_size_flags(SIZE_EXPAND_FILL);
			item_editor->set_stretch_ratio(1.5);
			item_editor->set_base_type("StyleBox");
			if (E.value) {
				if (edited_theme->has_stylebox(E.key, edited_type)) {
					item_editor->set_edited_resource(edited_theme->get_stylebox(E.key, edited_type));
				} else {
					item_editor->set_edited_resource(Ref<Resource>());
				}
				item_editor->connect("resource_selected", callable_mp(this, &ThemeTypeEditor::_edit_resource_item));
				item_editor->connect("resource_changed", callable_mp(this, &ThemeTypeEditor::_stylebox_item_changed).bind(E.key));
				Button *pin_leader_button = memnew(Button);
				pin_leader_button->set_flat(true);
				pin_leader_button->set_toggle_mode(true);
				pin_leader_button->set_icon(get_theme_icon(SNAME("Pin"), SNAME("EditorIcons")));
				pin_leader_button->set_tooltip_text(TTR("Pin this StyleBox as a main style. Editing its properties will update the same properties in all other StyleBoxes of this type."));