JERUSALEM — Prayers at the Al-Aqsa Mosque ended peacefully on Friday amid two weeks of unrest over security devices at the major holy site in Jerusalem, Israeli police said, but violence flared in the West Bank, where a Palestinian was killed after he attacked soldiers and another died in clashes along Gaza’s border with Israel. Tensions have been high since Arab gunmen killed two police officers in the sacred Jerusalem compound on July 14, prompting Israel to install security devices at entrances to the site that is holy to both Muslims and Jews. The move outraged Muslims and sparked some of the worst street clashes in years, threatening to draw Israel into conflict with other Arab and Muslim nations.