Error on `NULL["field_name"]`: The expression to get an indexed field is only valid for `List`, `Struct`, or `Map` types, got Null

[alamb]

Describe the bug

Expr::field is broken for ScalarValue::Null

After #10375 merged Expr::field is broken when we try and do it on ScalarValue::Null (in addition to #10565)

If you try to use it, you get an error:

The expression to get an indexed field is only valid for List, Struct, or Map types, got Null

To Reproduce

Add this test to expr_fn

#[test]
fn test_get_field_null() {
    evaluate_expr_test(
        lit(ScalarValue::Null).field("a"),
        vec![
            "+------------+",
            "| NULL literal",
        ],
    );
}

Fails with:

called Result::unwrap() on an Err value: Plan("The expression to get an indexed field is only valid for List, Struct, or Map types, got Null")

Expected behavior

Result should also be a NULL scalar

Additional context

No response