Dolt: `DISTINCT` window output with a composite outer sort reaches a stale field index

## What happened

`DISTINCT` window output with a composite outer sort reaches a stale field index.
Removing `DISTINCT` returns the expected rows.

## Environment

Dolt main commit `59fb843bf6a4b653d7c8b6d997a603b10cf279d9` (`dolt version 2.2.3`).

## How to reproduce

```sql
CREATE TABLE t(id INT PRIMARY KEY,g INT NOT NULL,k INT NOT NULL);
INSERT INTO t VALUES (1,0,0),(2,0,1),(3,0,2);

SELECT DISTINCT g,
RANK() OVER (PARTITION BY g ORDER BY k ASC) AS r
FROM t
ORDER BY g, 2;
```

The syntax is legal: `2` is the ordinal of the second projected column.

## Expected result

MySQL 8.0.43 fresh run:

The exact expected rows are:

```text
g r
0 1
0 2
0 3
```

This is also the result of an independent rank calculation followed by `DISTINCT` and the same outer ordering.

## Actual result

Dolt produces no rows and returns the same internal error in all three runs:

```text
unable to sort: unable to find field with index 4 in row of 2 columns.
This is a bug. Please file an issue here: https://github.com/dolthub/dolt/issues
```

Removing `DISTINCT` returns the expected rows.

Start by running the provided SQL reproduction on Dolt and compare it with the MySQL result. Trace the DISTINCT, window-function ranking, and composite outer ORDER BY handling, then add a regression test for the query. Done means the query returns the three expected rows without the stale field-index error.

Written by the indexing model from the issue text.