Facebook owner Meta Platforms beat analysts’ estimates for third-quarter revenue and profit on Wednesday, but warned of “significant acceleration” in infrastructure expenses related to its artificial-intelligence buildout, sending mixed signals about whether higher digital ad sales from its core social media business would continue to cover its massive AI investments.Shares of the Menlo Park, Calif.-based firm fell 2.5% in after-hours trading.The world’s biggest social media company, headed by CEO Mark Zuck ...