If Democrats want to take control of the Senate in November, winning Michigan is a must. Progressive candidate Abdul El-Sayed, who pulled off a razor-thin victory in last month’s primary, will face Republican Sen. Mike Rogers, and the race is widely considered a toss-up. A big risk for El-Sayed: a crucial bloc within the state’s Democratic electorate — Black voters — isn’t sold on him.El-Sayed’s victory over a well-funded, establishment-backed r…