Apple TV’s new limited series, “The Last Days of Ptolemy Grey,” feels every bit as overdue as the justice and redemption sought by its nonagenarian protagonist. “Ptolemy Grey” is a passion project for star and executive producer Samuel L. Jackson who has tirelessly hunted for a home for an adaptation of Walter Mosley’s novel since its release in 2010. It’s also, improbably, the first-ever series-length treatment of Mosley’s work, despite his prolific output and a narrative milieu full of the sexy mysteries prestige television thrives on. (To be fair, Amblin Television announced last year a series based on Mosley’s popular Easy Rawlins detective novels, the 15th of which was released last month.) While “Ptolemy” has flaws in its execution, it’s redeemed by earth-shaking performances, and justifies Jackson’s desire to spotlight a storyteller confined to…