Arm Holdings Plc, the chip designer that went public last year, gave a disappointing sales forecast for the current period, signaling that a still-recovering smartphone market may overshadow growth from artificial intelligence. Revenue will be $920 million to $970 million in the current period, which ends in December, the company said Wednesday. The midpoint of that range would fall short of the $950.9 million that analysts had estimated. Profit will be 32 to 36 cents a share, minus certain item...