LONDON — The Giants are re-signing former All-Pro safety Landon Collins to the practice squad, a source confirmed to the New York Daily News Thursday. Collins, 28, was the Giants’ best player in a win over the L.A. Rams in London in 2016. He was one of the team’s best players that season, the last time they made the playoffs. He will now meet the Giants overseas in London as they prepare to face the Green Bay Packers on Sunday at Tottenham Hotspur Stadium. The three-time Pro Bowler rejoins the team that drafted him in the second round of 2015. The news was first reported by insider Josina Ande…