(you don't have to strictly follow this form)

**Describe the bug**
When using `ORDER BY column_name COLLATE 'en'`, `COLLATE` is ignored if `column_name` is the primary key
 
**How to reproduce**
* version 21.1.2
* `CREATE TABLE` statements for all tables involved:
```
CREATE TABLE test.test_collation
(
    `v` String,
    `v2` String
)
ENGINE = MergeTree
ORDER BY v
SETTINGS index_granularity = 8192
```
* Sample data:
```
insert into test.test_collation values ('A', 'A')
insert into test.test_collation values ('B', 'B')
insert into test.test_collation values ('C', 'C')
insert into test.test_collation values ('a', 'a')
insert into test.test_collation values ('b', 'b')
insert into test.test_collation values ('c', 'c')
```
* Queries to run that lead to unexpected result
Primary key
```
SELECT *
FROM test.test_collation
ORDER BY v ASC COLLATE 'en'

Query id: fa84ae7a-abe7-4886-99cd-eba7ad5d5fc4

┌─v─┬─v2─┐
│ A │ A  │
│ B │ B  │
│ C │ C  │
│ a │ a  │
│ b │ b  │
│ c │ c  │
└───┴────┘
```
Separate column
```
SELECT *
FROM test.test_collation
ORDER BY v2 ASC COLLATE 'en'

Query id: 04401f85-3cb2-442c-8c89-e3328d1615cd

┌─v─┬─v2─┐
│ a │ a  │
│ A │ A  │
│ b │ b  │
│ B │ B  │
│ c │ c  │
│ C │ C  │
└───┴────┘
```

**Expected behavior**
Both of these queries to return the rows in the same order

: use_index_for_in_with_subqueries(settings_.use_index_for_in_with_subqueries)
    , size_limits_for_set(settings_.max_rows_in_set, settings_.max_bytes_in_set, settings_.set_overflow_mode)
{}
ExpressionAnalyzer::ExpressionAnalyzer(
    const ASTPtr & query_,
    const TreeRewriterResultPtr & syntax_analyzer_result_,
    ContextPtr context_,
    size_t subquery_depth_,
    bool do_global,
    SubqueriesForSets subqueries_for_sets_)
    : WithContext(context_)
    , query(query_), settings(getContext()->getSettings())
    , subquery_depth(subquery_depth_)
    , syntax(syntax_analyzer_result_)
{
    subqueries_for_sets = std::move(subqueries_for_sets_);
    
    
    initGlobalSubqueriesAndExternalTables(do_global);
    
    
    
    
    
    
    
    analyzeAggregation();
}
void ExpressionAnalyzer::analyzeAggregation()