### 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)

_THREAD_SAFE_METHOD_
	ERR_FAIL_COND(!windows.has(p_window));
	WindowData &wd = windows[p_window];
	if (wd.fullscreen || wd.maximized) {
		return;
	}
	int w = p_size.width;
	int h = p_size.height;
	wd.width = w;
	wd.height = h;
#if defined(VULKAN_ENABLED)
	if (context_vulkan) {
		context_vulkan->window_resize(p_window, w, h);
	}
#endif
#if defined(GLES3_ENABLED)
	if (gl_manager) {
		gl_manager->window_resize(p_window, w, h);
	}
#endif
	RECT rect;
	GetWindowRect(wd.hWnd, &rect);
	if (!wd.borderless) {
		RECT crect;
		GetClientRect(wd.hWnd, &crect);
		w += (rect.right - rect.left) - (crect.right - crect.left);
		h += (rect.bottom - rect.top) - (crect.bottom - crect.top);
	}
	MoveWindow(wd.hWnd, rect.left, rect.top, w, h, TRUE);
}