### 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
EditorUndoRedoManager *ur = EditorUndoRedoManager::get_singleton();
	ur->create_action(TTR("Set Color Item in Theme"), UndoRedo::MERGE_ENDS);
	ur->add_do_method(*edited_theme, "set_color", p_item_name, edited_type, p_value);
	ur->add_undo_method(*edited_theme, "set_color", p_item_name, edited_type, edited_theme->get_color(p_item_name, edited_type));
	ur->commit_action();
}
void ThemeTypeEditor::_constant_item_changed(float p_value, String p_item_name) {
	EditorUndoRedoManager *ur = EditorUndoRedoManager::get_singleton();
	ur->create_action(TTR("Set Constant Item in Theme"));
	ur->add_do_method(*edited_theme, "set_constant", p_item_name, edited_type, p_value);
	ur->add_undo_method(*edited_theme, "set_constant", p_item_name, edited_type, edited_theme->get_constant(p_item_name, edited_type));
	ur->commit_action();
}
void ThemeTypeEditor::_font_size_item_changed(float p_value, String p_item_name) {
	EditorUndoRedoManager *ur = EditorUndoRedoManager::get_singleton();
	ur->create_action(TTR("Set Font Size Item in Theme"));
	ur->add_do_method(*edited_theme, "set_font_size", p_item_name, edited_type, p_value);
	ur->add_undo_method(*edited_theme, "set_font_size", p_item_name, edited_type, edited_theme->get_font_size(p_item_name, edited_type));
	ur->commit_action();
}
void ThemeTypeEditor::_edit_resource_item(Ref<Resource> p_resource, bool p_edit) {