[FEA] Support grouped list aggregation and explode in cuDF-Polars

[rjzamora]

Grouped list aggregation is not currently supported by the GPU engine, which also blocks workflows that aggregate values into lists and then explode them back into rows.

def test_grouped_list_aggregation_explode(engine: GPUEngine) -> None:
    lf = pl.LazyFrame(
        {
            "g": [1, 1, 2, 2, 2],
            "x": [10, 20, 30, 40, 50],
        }
    )

    q = lf.group_by("g").agg(pl.col("x")).explode("x")

    assert_gpu_result_equal(q, engine=engine, check_row_order=False)

Related broad inventory issue: #23151