Yemen’s Houthi rebels could free a political leader with ties to the internationally recognized government who has been detained for nearly a decade, under a preliminary prisoner swap deal announced by the United Nations on Monday. Mohamed Qahtan is the leader of the Sunni Islamist Islah party, which is aligned with the Saudi Arabia-backed government, and he has been held incommunicado by the Iranian-backed Houthis since 2015, the United Nations said. The office of UN special envoy Hans Grundberg convened a meeting in Oman with the International Committee of the Red Cross over the weekend to f…