(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

{
            const auto & elem = ptr->as<const ASTWindowListElement &>();
            WindowDescription desc;
            desc.window_name = elem.name;
            makeWindowDescriptionFromAST(desc, elem.definition.get());
            auto [it, inserted] = window_descriptions.insert(
                {desc.window_name, desc});
            if (!inserted)
            {
                throw Exception(ErrorCodes::BAD_ARGUMENTS,
                    "Window '{}' is defined twice in the WINDOW clause",
                    desc.window_name);
            }
        }
    }
    
    for (const ASTFunction * function_node : syntax->window_function_asts)
    {
        assert(function_node->is_window_function);
        WindowFunctionDescription window_function;
        window_function.function_node = function_node;
        window_function.column_name
            = window_function.function_node->getColumnName();
        window_function.function_parameters
            = window_function.function_node->parameters
                ? getAggregateFunctionParametersArray(
                    window_function.function_node->parameters)
                : Array();