WASHINGTON — The National Prayer Breakfast, one of the most visible and long-standing events that brings religion and politics together in Washington, is splitting from the private religious group that had overseen it for decades, due to concerns the gathering had become too divisive.The organizer and host for this year’s breakfast, scheduled for Thursday, will be the National Prayer Breakfast Foundation, headed by former Sen. Mark Pryor, D-Ark.Sen. Chris Coons, a regular participant and chairman of the Senate …