### 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)

}
			mm->set_velocity(Input::get_singleton()->get_last_mouse_velocity());
			if (old_invalid) {
				old_x = mm->get_position().x;
				old_y = mm->get_position().y;
				old_invalid = false;
			}
			mm->set_relative(Vector2(mm->get_position() - Vector2(old_x, old_y)));
			old_x = mm->get_position().x;
			old_y = mm->get_position().y;
			if (receiving_window_id != window_id) {
				
				mm->set_position(mm->get_position() - window_get_position(receiving_window_id) + window_get_position(window_id));
				mm->set_global_position(mm->get_position());
			}
			Input::get_singleton()->parse_input_event(mm);
		} break;
		case WM_LBUTTONDOWN:
		case WM_LBUTTONUP:
			if (Input::get_singleton()->is_emulating_mouse_from_touch()) {
				
				LPARAM extra = GetMessageExtraInfo();
				if (IsTouchEvent(extra)) {
					break;
				}
			}
			[[fallthrough]];
		case WM_MBUTTONDOWN:
		case WM_MBUTTONUP:
		case WM_RBUTTONDOWN: