By Daina Beth Solomon MEXICO CITY/WASHINGTON (Reuters) – The United States has asked Mexico to probe alleged worker rights violations at an auto-parts plant owned by Italian-French carmaker Stellantis, the fourth such complaint under a revised trade deal, U.S. officials said on Monday. The U.S. request for Mexico to examine possible abuses at Teksid Hierro de Mexico in the northern border state of Coahuila comes under the 2020 United States-Mexico-Canada Agreement (USMCA). Teksid, which employs nearly 1,500 people and makes iron castings for heavy vehicles, has been embroiled in a union disput…