Aidin Vaziri | If any artist is primed for a career reboot, it’s Mary J. Blige. As one of the most commanding R&B vocalists of the ’90s, her legacy deserves better than the batch of irredeemably bland albums credited to her name over the past few years. She must know because for her 13th and latest studio recording, “The London Sessions,” Blige spent a month in — where else? — London, recording songs with the biggest and brightest English hit makers of the moment, including Disclosure, Naughty Boy and Emeli Sande. Sam Smith helped co-write four of the album’s most prominent tracks, such as the overwrought ballad “Not Loving You” and “Therapy.” But things really pick up when Blige reaches back to her hip-hop soul club days, propped by a set of beats that broadly touch on everything from U.K. garage (“My Loving”) to modern house (“Pick Me Up”).