49ers players were challenged by Kyle Shanahan to provoke a tantrum in DK Metcalf. On Sunday, the San Francisco 49ers defeated the Seattle Seahawks in a game that was tainted by a fight between Fred Warner and DK Metcalf. But it appears that the 49ers’ strategy included getting under Metcalf’s skin from the beginning. The San Francisco head coach, Kyle Shanahan, gave his players a challenge the night before at the team’s meeting to try to get the Seahawks receiver to lose his cool. According to reports, Shanahan also collected and displayed a number of videos showing Metcalf losing it…