Replace CN3791 with CN3801

[gardners]

CN3791 is for LiIon which has too high a charge Vmax of 4.2V+/- 1%, which will probably fry an LiFePO4 cell which break down at 4.2V.
CN3801 is designed for LiFePO4, and tops out at 3.625V instead.
Footprint and pin assignment etc is otherwise identical.

Not stocked by mouser or digikey, but LCSC stock them. I have ordered 10 for me here.