There are two options. Either the AI is intelligent and creative in the same sense as a human being, or the AI is an automaton doing nothing but following the instructions given to it by its creator(s).
In the first case, the art is Art; the AI is an artist.
In the second case, the art is also Art; the creator of the AI is the artist.
In the first case, the art is Art; the AI is an artist.
In the second case, the art is also Art; the creator of the AI is the artist.