fix: don't emit empty <dataAccelerationConfig/> on workbook update when unset - #1885

"Error! {\"statusCode\":200,\"statusMessage\":\"OK\",\"ok\":false,\"result\":\"{\\\"ok\\\":false,\\\"error\\\":\\\"missing_scope\\\",\\\"needed\\\":\\\"chat:write:bot\\\",\\\"provided\\\":\\\"incoming-webhook,commands\\\"}\",\"response\":{\"ok\":false,\"error\":\"missing_scope\",\"needed\":\"chat:write:bot\",\"provided\":\"incoming-webhook,commands\"}} (response)"