Dave McNary Film ReporterEmmy winner and “Succession” star Jeremy Strong is in talks to portray the writer John Gruenn in Bradley Cooper’s “Maestro,” the Leonard Bernstein biopic for Netflix.Strong won the Emmy last month for outstanding actor in a drama series for his portrayal of Kendall Roy in HBO’s “Succession.” He also plays Jerry Rubin in Netflix’s recent film “The Trial of the Chicago 7.” His other credits include “Lincoln,” “The Big Short” and “Molly’s Game.” Gruen wrote the authorized