[BUG] Simple window query fails

[comphead]

Describe the bug

Not sure if its a regression but simple window query fails.

To Reproduce

DataFusion CLI v26.0.0
❯ select sum(1) over() x, sum(1) over () y;
Arrow error: Invalid argument error: batches[0] schema is different with argument schema.
            batches[0] schema: Schema { fields: [Field { name: "placeholder_0", data_type: Null, nullable: true, dict_id: 0, dict_is_ordered: false, metadata: {} }], metadata: {} },
            argument schema: Schema { fields: [], metadata: {} }

Expected behavior

Should work.

Additional context

Found when working on #6492

[Jefffrey]

datafusion-cli$ cargo run
    Finished dev [unoptimized + debuginfo] target(s) in 0.20s
     Running `/media/jeffrey/1tb_860evo_ssd/.cargo_target_cache/debug/datafusion-cli`
DataFusion CLI v32.0.0
❯ select sum(1) over() x, sum(1) over () y;
+---+---+
| x | y |
+---+---+
| 1 | 1 |
+---+---+
1 row in set. Query took 0.004 seconds.

❯

Issue looks resolved as of latest main.

I've also created PR in case want this test case added to prevent future regression: #7928

(Assuming that is the expected result)