Performance of ORDER BY on sorting key prefix with braces is 2x slower than without due to inefficient execution plan.
Without braces:
```sql
EXPLAIN PIPELINE
SELECT
    CounterID,
    EventDate
FROM hits_v1
ORDER BY
    CounterID ASC,
    EventDate ASC

┌─explain───────────────────────────┐
│ (Expression)                      │
│ ExpressionTransform               │
│   (Sorting)                       │
│   MergingSortedTransform 19 → 1   │
│     (Expression)                  │
│     ExpressionTransform × 19      │
│       (ReadFromMergeTree)         │
│       MergeTreeInOrder × 19 0 → 1 │
└───────────────────────────────────┘
```
With braces:
```sql
EXPLAIN PIPELINE
SELECT
    CounterID,
    EventDate
FROM hits_v1
ORDER BY (CounterID, EventDate) ASC

┌─explain────────────────────────────────┐
│ (Expression)                           │
│ ExpressionTransform                    │
│   (Sorting)                            │
│   MergingSortedTransform 16 → 1        │
│     MergeSortingTransform × 16         │
│       LimitsCheckingTransform × 16     │
│         PartialSortingTransform × 16   │
│           (Expression)                 │
│           ExpressionTransform × 16     │
│             (ReadFromMergeTree)        │
│             MergeTreeThread × 16 0 → 1 │
└────────────────────────────────────────┘
```
{
        bool exists_expression = func.name == "exists"
            && func.arguments && func.arguments->children.size() == 1
            && typeid_cast<const ASTSubquery *>(func.arguments->children[0].get());
        if (!exists_expression)
            return;
        
        auto subquery_node = func.arguments->children[0];
        auto table_expression = std::make_shared<ASTTableExpression>();
        table_expression->subquery = std::move(subquery_node);
        table_expression->children.push_back(table_expression->subquery);
        auto tables_in_select_element = std::make_shared<ASTTablesInSelectQueryElement>();
        tables_in_select_element->table_expression = std::move(table_expression);
        tables_in_select_element->children.push_back(tables_in_select_element->table_expression);
        auto tables_in_select = std::make_shared<ASTTablesInSelectQuery>();
        tables_in_select->children.push_back(std::move(tables_in_select_element));
        auto select_expr_list = std::make_shared<ASTExpressionList>();