### 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
import_bulk_sc->set_custom_minimum_size(Size2(260.0, 0.0) * EDSCALE);
	import_bulk_sc->set_horizontal_scroll_mode(ScrollContainer::SCROLL_MODE_DISABLED);
	import_main_hb->add_child(import_bulk_sc);
	VBoxContainer *import_bulk_vb = memnew(VBoxContainer);
	import_bulk_vb->set_h_size_flags(Control::SIZE_EXPAND_FILL);
	import_bulk_sc->add_child(import_bulk_vb);
	Label *import_bulk_label = memnew(Label);
	import_bulk_label->set_text(TTR("Select by data type:"));
	import_bulk_vb->add_child(import_bulk_label);
	select_colors_icon = memnew(TextureRect);
	select_colors_label = memnew(Label);
	deselect_all_colors_button = memnew(Button);
	select_all_colors_button = memnew(Button);
	select_full_colors_button = memnew(Button);
	total_selected_colors_label = memnew(Label);
	select_constants_icon = memnew(TextureRect);
	select_constants_label = memnew(Label);
	deselect_all_constants_button = memnew(Button);
	select_all_constants_button = memnew(Button);
	select_full_constants_button = memnew(Button);
	total_selected_constants_label = memnew(Label);
	select_fonts_icon = memnew(TextureRect);
	select_fonts_label = memnew(Label);
	deselect_all_fonts_button = memnew(Button);
	select_all_fonts_button = memnew(Button);
	select_full_fonts_button = memnew(Button);
	total_selected_fonts_label = memnew(Label);
	select_font_sizes_icon = memnew(TextureRect);
	select_font_sizes_label = memnew(Label);
	deselect_all_font_sizes_button = memnew(Button);