Dak Prescott, the injured Dallas Cowboys quarterback, is a participant – of a sort – in the team’s Thursday workout here at The Star. FRISCO – The stitches in Dak Prescott’s surgically repaired thumb and hand have yet to be removed. But the injured Dallas Cowboys quarterback is nevertheless a participant – of a sort – in the team’s Thursday workout here at The Star. This marks a first since the fractured thumb was sustained in the team’s Week 1 loss to the Tampa Bay Buccaneers on Sept. 11. A week ago, Dak was not practicing, but he was present…