A leading Palestinian newspaper editor in East Jerusalem has been ordered expelled on the grounds that his support for the Palestine Liberation Organization constitutes a danger to Israel's security. Akram Haniya, editor of the Arabic-language daily newspaper Al Shaab (The People), was arrested at his home in the occupied West Bank town of Ramallah. Israeli military sources were quoted as describing him as a leading PLO activist and said his journalistic work was subsidized by the guerrilla organization. Haniya, 35, is chairman of the Palestinian Journalists' Assn. in the West Bank and a short-story writer. He said he will appeal the expulsion order.