PostgreSQL compatibility: `SIMILAR TO` should treat `%` as a wildcard

Split out from #22247.

### Mismatch

`SIMILAR TO` should treat `%` as a wildcard.

```sql
SELECT 'abc' SIMILAR TO 'a%';
```

PostgreSQL:

```text
true
```

DataFusion:

```text
false
```

### Expected behavior

For PostgreSQL-compatible SQL semantics, DataFusion should either match PostgreSQL's result or raise the same class of domain/semantic error.
