Another quarterback contract domino fell Thursday night. It was in Jacksonville, where Trevor Lawrence signed a five-year contract worth $275 million, including $200 million guaranteed. But there’s still a big one left on the board in Dallas where Dak Prescott is entering the final year of his four-year, $160 million extension. With OTAs and mandatory minicamp in the books, Prescott and the Cowboys are still working to get a new contract together, and Lawrence’s extension added another layer to the discussion. In fact, according to NFL Network’s Ian Rapoport, Prescott could be looking at an ev…