### 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_INDEX_MSG(p_data_type, Theme::DATA_TYPE_MAX, "Theme item data type is out of bounds.");
	Label *total_selected_items_label = nullptr;
	switch (p_data_type) {
		case Theme::DATA_TYPE_COLOR:
			total_selected_items_label = total_selected_colors_label;
			break;
		case Theme::DATA_TYPE_CONSTANT:
			total_selected_items_label = total_selected_constants_label;
			break;
		case Theme::DATA_TYPE_FONT:
			total_selected_items_label = total_selected_fonts_label;
			break;
		case Theme::DATA_TYPE_FONT_SIZE:
			total_selected_items_label = total_selected_font_sizes_label;