"Light Trail Mode" isn't a thing on any device, from what I can tell. What you are referring to is long exposure, and the Camera app already allows you to do this. Go to "More">"Pro">the fstop and shutter speed button (the second from the left)>choose a longer exposure time. The bigger the number (if it is a fraction, the smaller the denominator), the longer the time that the image sensor is allowed to capture image data. This is how you capture "light trails" and the night sky. Often, you can adjust other settings as well to improve your long exposure photos.
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