Unparser with PostgreSqlDialect fails after Optimization Pass

### Describe the bug

The Unparser has a bug in the way that it treats certain PostgreSQL formatted queries, after optimization, which seems to be because `requires_derived_table_alias` is `true`:

I.e, optimizing then unparsing this query with postgresql dialect breaks:

```sql
WITH base AS (SELECT name, salary FROM t)
SELECT name,
CASE WHEN SUM(salary) > 0 THEN 1 ELSE 0 END AS x,
CASE WHEN SUM(salary) > 0 THEN SUM(salary) ELSE 0 END AS y
FROM base GROUP BY name
```

### To Reproduce

Here's a test we can add somewhere that fails:

```rust
#[tokio::test]
async fn test_cse_derived_projection_roundtrip() {
let ctx = SessionContext::new();
ctx.sql("CREATE TABLE t (name TEXT, salary DOUBLE) AS VALUES ('a', 1.0), ('b', 2.0)")
.await.unwrap().collect().await.unwrap();

let sql = "\
WITH base AS (SELECT name, salary FROM t) \
SELECT name, \
CASE WHEN SUM(salary) > 0 THEN 1 ELSE 0 END AS x, \
CASE WHEN SUM(salary) > 0 THEN SUM(salary) ELSE 0 END AS y \
FROM base GROUP BY name";

let df = ctx.sql(sql).await.unwrap();
let optimized = ctx.state().optimize(df.logical_plan()).unwrap();
let unparser = Unparser::new(&datafusion_sql::unparser::dialect::PostgreSqlDialect {});
let unparsed = unparser.plan_to_sql(&optimized).unwrap().to_string();

ctx.sql(&unparsed).await.unwrap_or_else(|e| {
panic!("Roundtrip failed.\n\nOriginal: {sql}\nUnparsed: {unparsed}\nError: {e}")
});
}
```

This fails with the following error message on `main`:

```
Roundtrip failed.

Original: WITH base AS (SELECT name, salary FROM t) SELECT name, CASE WHEN SUM(salary) > 0 THEN 1 ELSE 0 END AS x, CASE WHEN SUM(salary) > 0 THEN SUM(salary) ELSE 0 END AS y FROM base GROUP BY name
Unparsed: SELECT "base"."name", CASE WHEN "__common_expr_1" THEN 1 ELSE 0 END AS "x", CASE WHEN "__common_expr_1" THEN "sum(base.salary)" ELSE 0.0 END AS "y" FROM (SELECT (sum("base"."salary") > 0.0) AS "__common_expr_1", "base"."name", sum("base"."salary") FROM "t" AS "base" GROUP BY "base"."name") AS "derived_projection"
Error: Schema error: No field named base.name. Valid fields are derived_projection.__common_expr_1, derived_projection.name, derived_projection."sum(base.salary)".
```

### Expected behavior

This should parse correctly

### Additional context

_No response_

Start with the supplied test_cse_derived_projection_roundtrip reproduction and trace Unparser output for the PostgreSqlDialect after optimization. Inspect how requires_derived_table_alias affects the derived projection and verify the unparsed SQL can be parsed and executed successfully for the shown query.

Written by the indexing model from the issue text.