AT&T beat Wall Street estimates for wireless subscriber additions in the first quarter on Wednesday, driven by steady demand for its plans that bundled high-speed fiber services and 5G mobile offerings. The U.S. wireless carrier's focus on bundling to fend off intense competition in a saturating market and aggressive trade-in offers helped it gain 324,000 net monthly bill-paying wireless phone subscribers.That compared with FactSet estimates of 258,300 additions for the quarter. After flagging elevated rate ...