### Godot version

v4.0.beta17.mono.official [c40020513]

### System information

Windows 11 22H2

### Issue description

If a focused subwindow is destroyed, DisplayServerWindows may still attempt to send mouse motion events to that window, because `last_focused_window` isn't updated until another window is focused.

```
ERROR: Condition "!windows.has(p_window)" is true. Returning: Point2i()
   at: window_get_position (platform/windows/display_server_windows.cpp:999)
```

### Steps to reproduce

Run the MRP, click some non-Godot application window to focus it, then click the "CLOSE" button in the secondary window. This destroys the window without re-focusing the main window, so hovering the mouse over the main window will produce the error message above.

### Minimal reproduction project

[native_windows_hover.zip](https://github.com/godotengine/godot/files/10573386/native_windows_hover.zip)

}
#define MI_WP_SIGNATURE 0xFF515700
#define SIGNATURE_MASK 0xFFFFFF00
#define IsPenEvent(dw) (((dw)&SIGNATURE_MASK) == MI_WP_SIGNATURE)
#define IsTouchEvent(dw) (IsPenEvent(dw) && ((dw)&0x80))
void DisplayServerWindows::_touch_event(WindowID p_window, bool p_pressed, float p_x, float p_y, int idx) {
	if (touch_state.has(idx) == p_pressed) {
		return;
	}
	if (p_pressed) {
		touch_state.insert(idx, Vector2(p_x, p_y));
	} else {
		touch_state.erase(idx);
	}
	Ref<InputEventScreenTouch> event;
	event.instantiate();
	event->set_index(idx);
	event->set_window_id(p_window);
	event->set_pressed(p_pressed);
	event->set_position(Vector2(p_x, p_y));
	Input::get_singleton()->parse_input_event(event);
}
void DisplayServerWindows::_drag_event(WindowID p_window, float p_x, float p_y, int idx) {