Incorrect to_builtins convertion with builtin_types=(frozendict,) #1104

def test_frozendict_builtin_types(self):
    msg = to_builtins(frozendict({"test": 1}), builtin_types=(frozendict,))
    assert type(msg) is frozendict
    assert msg == frozendict({"test": 1})

    msg = to_builtins(
        frozendict(
            {
                "test": frozendict({1: "a"}),
                FruitStr.BANANA: 1,
                "b": [FruitInt.APPLE],
            }
        ),
        builtin_types=(frozendict,),
    )
    assert type(msg) is frozendict
    assert type(msg["test"]) is frozendict
    assert type(list(msg.keys())[1]) is str
    assert msg == frozendict({
        "test": frozendict({1: "a"}),
        "banana": 1,
        "b": [-1],
    })