General Motors Co.’s second-quarter profits dropped roughly 40% year-over-year amid nagging supply-chain disruptions, even as the Detroit automaker forecast production improvements in the second half of the year and maintained its full-year earnings guidance. GM on Tuesday reported $1.7 billion in net income for the April-June period, down from $2.8 billion in the same period last year. But the automaker generated $35.8 billion in revenue in 2Q, up from $34.2 billion in the second quarter of 2021. Executives said the quarter’s results reflected the impacts of supply-chain disruptions that were…