### 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)

mb->set_pressed(true);
					mb->set_button_index(MouseButton::RIGHT);
				} break;
				case WM_RBUTTONUP: {
					mb->set_pressed(false);
					mb->set_button_index(MouseButton::RIGHT);
				} break;
				case WM_LBUTTONDBLCLK: {
					mb->set_pressed(true);
					mb->set_button_index(MouseButton::LEFT);
					mb->set_double_click(true);
				} break;
				case WM_RBUTTONDBLCLK: {
					mb->set_pressed(true);
					mb->set_button_index(MouseButton::RIGHT);
					mb->set_double_click(true);
				} break;
				case WM_MBUTTONDBLCLK: {
					mb->set_pressed(true);
					mb->set_button_index(MouseButton::MIDDLE);
					mb->set_double_click(true);
				} break;
				case WM_MOUSEWHEEL: {
					mb->set_pressed(true);
					int motion = (short)HIWORD(wParam);
					if (!motion) {
						return 0;
					}
					if (motion > 0) {
						mb->set_button_index(MouseButton::WHEEL_UP);