(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

&& storage && query.groupBy();
            query_analyzer.appendGroupBy(chain, only_types || !first_stage, optimize_aggregation_in_order, group_by_elements_actions);
            query_analyzer.appendAggregateFunctionsArguments(chain, only_types || !first_stage);
            before_aggregation = chain.getLastActions();
            finalize_chain(chain);
            if (query_analyzer.appendHaving(chain, only_types || !second_stage))
            {
                before_having = chain.getLastActions();
                chain.addStep();
            }
        }
        bool join_allow_read_in_order = true;
        if (hasJoin())
        {
            
            join_has_delayed_stream = query_analyzer.analyzedJoin().needStreamWithNonJoinedRows();
            join_allow_read_in_order = typeid_cast<HashJoin *>(join.get()) && !join_has_delayed_stream;
        }
        optimize_read_in_order =
            settings.optimize_read_in_order
            && storage && query.orderBy()
            && !query_analyzer.hasAggregation()
            && !query_analyzer.hasWindow()
            && !query.final()
            && join_allow_read_in_order;
        
        query_analyzer.appendSelect(chain, only_types || (need_aggregate ? !second_stage : !first_stage));
        
        
        if (has_window)