config: librem5: Use full resolution for the big cam

From my testing it seems the latest kernel fixes also stabilized full resolution mode, so if testing by others shows the same results this now may become viable.

We may still want to wait for https://source.puri.sm/Librem5/linux-next/-/issues/318 though, as otherwise full res photos are brighter than the preview, making it hard to shot correctly exposed photos (an alternative could be to adjust the total integration time to match across all modes, but that would make the preview slower as low res mode currently takes advantage of its low resness to make FPS a bit higher).