[BUG] No output callbacks with clientside_callback

[T4rk1n]

If a clientside callback has no output, it generate ID not found in layout error:

clientside_callback(
    """
    function(_) {
        window.location.reload();
    }
    """,
    Input("reset-button", "n_clicks"),
    prevent_initial_call=True,
)

[nhoover]

Thanks for this fix - works great!! 👍