series equality panics on series of empty structs

[universalmind303]

Polars version checks

• I have checked that this issue has not already been reported.

• I have confirmed this bug exists on the latest version of Polars.

Issue description

comparing a series of empty structs panics.

Reproducible example

use polars::prelude::*;
fn main() {
    let dtype = DataType::Struct(vec![]);
    let empties = vec![AnyValue::StructOwned(Box::new((vec![], vec![]))); 3];
    let s = Series::from_any_values_and_dtype("", &empties, &dtype).unwrap();
    let s2 = s.clone();
    assert!(s.series_equal_missing(&s2));
}

Expected behavior

does not panic.

Installed versions

polars = {git = "https://github.com/pola-rs/polars.git", branch = "master", features = ["dtype-full"]}

[stinodego]

Empty structs are not supported yet.

Closing in favor of #9216