### 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)

return mouse_mode;
}
void DisplayServerWindows::warp_mouse(const Point2i &p_position) {
	_THREAD_SAFE_METHOD_
	WindowID window_id = _get_focused_window_or_popup();
	if (!windows.has(window_id)) {
		return; 
	}
	if (mouse_mode == MOUSE_MODE_CAPTURED) {
		old_x = p_position.x;
		old_y = p_position.y;
	} else {
		POINT p;
		p.x = p_position.x;
		p.y = p_position.y;
		ClientToScreen(windows[window_id].hWnd, &p);
		SetCursorPos(p.x, p.y);
	}
}
Point2i DisplayServerWindows::mouse_get_position() const {
	POINT p;
	GetCursorPos(&p);
	return Point2i(p.x, p.y) - _get_screens_origin();
}
BitField<MouseButtonMask> DisplayServerWindows::mouse_get_button_state() const {
	return last_button_state;
}
void DisplayServerWindows::clipboard_set(const String &p_text) {