Microsoft, showing its endurance in the mobile phone business, is expected to announce on Monday a partnership with the largest contract electronics manufacturer, Flextronics of Singapore, to make low-cost smart phones that run on Microsoft's mobile operating system. . The device, in a so-called candy-bar design, will have the interactive features of a smart phone at the price of many standard mobile phones today, Microsoft executives said in advance of the opening on Monday of the 3GSM World Congress, the mobile phone industry's annual trade show in Cannes. . Microsoft began making software to power mobile phones five years ago...