### 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)

iconinfo.yHotspot = p_hotspot.y;
			iconinfo.hbmMask = mask;
			iconinfo.hbmColor = bitmap;
			cursors[p_shape] = CreateIconIndirect(&iconinfo);
		}
		Vector<Variant> params;
		params.push_back(p_cursor);
		params.push_back(p_hotspot);
		cursors_cache.insert(p_shape, params);
		if (p_shape == cursor_shape) {
			if (mouse_mode == MOUSE_MODE_VISIBLE || mouse_mode == MOUSE_MODE_CONFINED) {
				SetCursor(cursors[p_shape]);
			}
		}
		DeleteObject(mask);
		DeleteObject(bitmap);
		ReleaseDC(nullptr, dc);
	} else {
		
		if (cursors[p_shape]) {
			DestroyIcon(cursors[p_shape]);
		}
		cursors[p_shape] = nullptr;
		CursorShape c = cursor_shape;
		cursor_shape = CURSOR_MAX;
		cursor_set_shape(c);
		cursors_cache.erase(p_shape);
	}
}
bool DisplayServerWindows::get_swap_cancel_ok() {