You should be able to just remove it. As an example, my refrigerator
has as an option an ice maker that I can install, and there is an
electrical connector flush to the inside wall that I can connect it
to. Presumaby therewould also be a hole in the refrigerator somewhere
where the water line used to be that you would have to plug.

I am assuming that your ice maker is entirely inside the refrigerator,
as opposed to the type with a feed in the door (which you can probably
also just disconnect, but I personally wouldn't know).