In a landmark moment for global entertainment, legendary filmmaker Steven Spielberg has officially joined the exclusive EGOT club — a distinction reserved for artists who have won an Emmy, Grammy, Oscar and Tony Award — after securing his first Grammy Award at the 68th Annual Grammy Awards. Spielberg, 79, earned the Grammy for Best Music Film as a producer of the documentary Music by John Williams, which celebrates the life and work of his longtime collaborator, the iconic composer John Williams. This Grammy award completes the quartet of major entertainment honors that define an EGOT — a rare feat achieved…