Fixed navigation in custom_spa_server_on_free_port

[sensiblearts]

Now that navigation is fixed (Thank you! @hassandraga ), I had to fix the navigation my the example -- because I wrote it when webui navigation was not working on Windows release mode. The new code:

 .EVENT_NAVIGATION => {
            const url = e.getString();
            if (std.mem.eql(u8, url, home_url)) {
                var win = e.getWindow();
                std.debug.print("WebUI.js is Starting navigation to: {s}\n", .{url});
                win.navigate(url);
            } else {
                std.debug.print("Client JS is navigating to: {s}\n", .{url});
            }