### 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
if (tool != TOOL_RULER) {
		ruler_tool_active = false;
		return false;
	}
	Ref<InputEventMouseButton> b = p_event;
	Ref<InputEventMouseMotion> m = p_event;
	Point2 previous_origin = ruler_tool_origin;
	if (!ruler_tool_active) {
		ruler_tool_origin = snap_point(viewport->get_local_mouse_position() / zoom + view_offset);
	}
	if (b.is_valid() && b->get_button_index() == MouseButton::LEFT) {
		if (b->is_pressed()) {
			ruler_tool_active = true;
		} else {
			ruler_tool_active = false;
		}
		viewport->queue_redraw();
		return true;
	}
	if (m.is_valid() && (ruler_tool_active || (grid_snap_active && previous_origin != ruler_tool_origin))) {
		viewport->queue_redraw();
		return true;
	}
	return false;
}
bool CanvasItemEditor::_gui_input_hover(const Ref<InputEvent> &p_event) {