(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

SelectQueryExpressionAnalyzer & query_analyzer,
        const StorageMetadataPtr & metadata_snapshot,
        bool first_stage_,
        bool second_stage_,
        bool only_types,
        const FilterDAGInfoPtr & filter_info_,
        const Block & source_header)
    : first_stage(first_stage_)
    , second_stage(second_stage_)
    , need_aggregate(query_analyzer.hasAggregation())
    , has_window(query_analyzer.hasWindow())
{
    
    
    /** First we compose a chain of actions and remember the necessary steps from it.
        *  Regardless of from_stage and to_stage, we will compose a complete sequence of actions to perform optimization and
        *  throw out unnecessary columns based on the entire query. In unnecessary parts of the query, we will not execute subqueries.
        */
    const ASTSelectQuery & query = *query_analyzer.getSelectQuery();
    auto context = query_analyzer.getContext();
    const Settings & settings = context->getSettingsRef();
    const ConstStoragePtr & storage = query_analyzer.storage();
    bool finalized = false;
    size_t where_step_num = 0;
    auto finalize_chain = [&](ExpressionActionsChain & chain)