### 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)

register_create_function("windows", create_func, get_rendering_drivers_func);
}
DisplayServerWindows::~DisplayServerWindows() {
	delete joypad;
	touch_state.clear();
	cursors_cache.clear();
	if (mouse_monitor) {
		UnhookWindowsHookEx(mouse_monitor);
	}
	if (user_proc) {
		SetWindowLongPtr(windows[MAIN_WINDOW_ID].hWnd, GWLP_WNDPROC, (LONG_PTR)user_proc);
	}
	
	screen_set_keep_on(false);
#ifdef GLES3_ENABLED
	
	
#endif
	if (windows.has(MAIN_WINDOW_ID)) {
#ifdef VULKAN_ENABLED
		if (context_vulkan) {
			context_vulkan->window_destroy(MAIN_WINDOW_ID);
		}
#endif
		if (wintab_available && windows[MAIN_WINDOW_ID].wtctx) {
			wintab_WTClose(windows[MAIN_WINDOW_ID].wtctx);