### 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
edited_theme->get_stylebox_type_list(&types);
		for (const StringName &E : types) {
			names.clear();
			edited_theme->get_stylebox_list(E, &names);
			for (const StringName &F : names) {
				if (stylebox_item == edited_theme->get_stylebox(F, E)) {
					belongs_to_theme = true;
					break;
				}
			}
		}
	} else if (Object::cast_to<Texture2D>(p_node)) {
		Ref<Texture2D> icon_item = Object::cast_to<Texture2D>(p_node);
		List<StringName> types;
		List<StringName> names;
		edited_theme->get_icon_type_list(&types);
		for (const StringName &E : types) {
			names.clear();
			edited_theme->get_icon_list(E, &names);
			for (const StringName &F : names) {
				if (icon_item == edited_theme->get_icon(F, E)) {
					belongs_to_theme = true;
					break;
				}
			}
		}
	}
	return belongs_to_theme;
}
void ThemeEditorPlugin::make_visible(bool p_visible) {