No, you should
not drive the car. While it might seem drivable, a missing or broken temperature sensor can cause serious engine damage. The engine management system relies on this sensor to control things like fuel mixture and ignition timing. Driving without it could lead to overheating, which can warp the cylinder head, crack the block, or cause other expensive repairs.
Get the sensor replaced by your mechanic (or a different one if you're not confident in their work) before driving the car again. Driving it with a faulty temperature sensor could negate any benefit from the new engine.
