WASHINGTON (Reuters) -Relatives of victims killed in recent mass shootings in New York state and Texas as well as a fourth grader who survived last week’s attack will speak before two congressional panels next week as U.S. lawmakers weigh new measures to curb gun violence. The mother of one of the 10 people killed at a supermarket in Buffalo, New York, will join the parents of one of the 19 children gunned down at a Uvalde, Texas, elementary school at the House of Representatives Oversight and Reform Committee’s hearing on June 8, the panel said on Friday. Miah Cerrillo, a fourth-grader at the…