### 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)

case WM_RBUTTONUP:
		case WM_MOUSEWHEEL:
		case WM_MOUSEHWHEEL:
		case WM_LBUTTONDBLCLK:
		case WM_MBUTTONDBLCLK:
		case WM_RBUTTONDBLCLK:
		case WM_XBUTTONDBLCLK:
		case WM_XBUTTONDOWN:
		case WM_XBUTTONUP: {
			Ref<InputEventMouseButton> mb;
			mb.instantiate();
			mb->set_window_id(window_id);
			switch (uMsg) {
				case WM_LBUTTONDOWN: {
					mb->set_pressed(true);
					mb->set_button_index(MouseButton::LEFT);
				} break;
				case WM_LBUTTONUP: {
					mb->set_pressed(false);
					mb->set_button_index(MouseButton::LEFT);
				} break;
				case WM_MBUTTONDOWN: {
					mb->set_pressed(true);
					mb->set_button_index(MouseButton::MIDDLE);
				} break;
				case WM_MBUTTONUP: {
					mb->set_pressed(false);
					mb->set_button_index(MouseButton::MIDDLE);
				} break;
				case WM_RBUTTONDOWN: {