WASHINGTON — Eight years ago, Kevin McCarthy, then the House Republican leader, embarked on a push to recruit more Black Republicans to run for Congress, arguing that the GOP needed to diversify to survive.By 2022, his efforts had yielded modest success, helping pave the way for four Black Republicans to be elected to the House that year, which boosted the total number of Black Republicans serving in Congress to five, including Sen. Tim Scott of South Carolina. That progress is about to be erased. All four Black Republicans in the House are leaving Congress next year: Three are seeking statewide...