### 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)

windows[MAIN_WINDOW_ID].wtctx = 0;
		}
		DestroyWindow(windows[MAIN_WINDOW_ID].hWnd);
	}
#if defined(VULKAN_ENABLED)
	if (rendering_device_vulkan) {
		rendering_device_vulkan->finalize();
		memdelete(rendering_device_vulkan);
		rendering_device_vulkan = nullptr;
	}
	if (context_vulkan) {
		memdelete(context_vulkan);
		context_vulkan = nullptr;
	}
#endif
	if (restore_mouse_trails > 1) {
		SystemParametersInfoA(SPI_SETMOUSETRAILS, restore_mouse_trails, 0, 0);
	}
#ifdef GLES3_ENABLED
	if (gl_manager) {
		memdelete(gl_manager);
		gl_manager = nullptr;
	}
#endif
	if (tts) {
		memdelete(tts);
	}
	CoUninitialize();
}