The chairman of the Senate Armed Services Committee will attend a benefit dinner next week to raise awareness and donations for the family of a former Marine sergeant who has been imprisoned in Iran for nearly two years. Sen. Carl Levin, D-Mich., is slated to attend the Free Amir Benefit Dinner in his home state on Wednesday. The benefit will be hosted by the family of Amir Hekmati, a former Marine sergeant who served four years in the Corps and deployed to Iraq. Hekmati was arrested in Iran while visiting his grandmother in August of 2011. He has been held ever since…