KYIV, Ukraine — The Pentagon has seen “indications” that the North Korean forces who have been sent to Russia to help the Kremlin in its war against Ukraine have suffered their first casualties, according to a U.S. official. Air Force Maj. Gen. Pat Ryder, the Pentagon spokesman, told reporters on Monday that the North Koreans had entered combat last week in the Russian region of Kursk. Russia has been trying to recapture territory in the region…