(Reuters) -Washington State Attorney General Bob Ferguson filed a lawsuit on Tuesday to block grocery chain Albertsons Cos Inc from paying dividends to shareholders before closure of its proposed merger with supermarket operator Kroger Co. The $4 billion payout to shareholders “risks severely undercutting the grocery giant’s ability to compete during the lengthy time period government regulators — including Washington — will be scrutinizing the merger,” according to a statement posted to the Washington Attorney General’s website. Kroger had snapped up Albertsons in a $25 billion deal last mont…