Samsung scored bragging rights to the world's top-selling smartphone in the third quarter with its Galaxy S3. But the South Korean electronics giant will face stiff competition in the fourth quarter from Apple's (AAPL) new iPhone 5. Samsung, with its Galaxy S3, surpassed Apple for the first time, research firm Strategy Analytics said Thursday. Apple's new smartphone for most of Q3, the iPhone 4S, launched in October 2011. The Galaxy S3 started