The fresnel depends on the angles related to the camera and the shapes of the object respect to the camera. The camera for baking is ortographic, and the shapes when baking (the UVs) are totally flattened. So it cannot be baked into a texture, it’s an effect that can only be produced in the material.
Anyway I don’t know which is the purpose of baking everything, you could just put later the fresnel in the material and mix it then with the rest baked.
Or you could, instead of using the fresnel, use the geometry node taking inputs that don’t depend on the camera angle, but with similar effect, for example normal, tangent, true normal, etc. Those you could bake them.