21.7.3 throws an exception if `_sample_factor` is used in a query:
```
CREATE TABLE sessions
(
  `user_id` UInt64
)
ENGINE = MergeTree
ORDER BY user_id 
SAMPLE BY user_id;

insert into sessions values(1);

SELECT
    sum(user_id * _sample_factor) 
FROM sessions
SAMPLE 10000000

DB::Exception: Cannot find column `user_id` in source stream (version 21.8.1.7409 (official build))

SELECT
    sum(user_id) 
FROM sessions
SAMPLE 10000000

sum(user_id)
------------
           1
```
No exception on 21.6.5
#include <Processors/QueryPlan/ReadFromMergeTree.h>
#include <Processors/QueryPipeline.h>
#include <Processors/ConcatProcessor.h>
#include <Processors/Transforms/ReverseTransform.h>
#include <Processors/Transforms/ExpressionTransform.h>
#include <Processors/Transforms/FilterTransform.h>
#include <Processors/Transforms/AddingSelectorTransform.h>
#include <Processors/Transforms/CopyTransform.h>
#include <Processors/Sources/NullSource.h>
#include <Processors/Merges/AggregatingSortedTransform.h>
#include <Processors/Merges/CollapsingSortedTransform.h>
#include <Processors/Merges/MergingSortedTransform.h>
#include <Processors/Merges/ReplacingSortedTransform.h>
#include <Processors/Merges/SummingSortedTransform.h>
#include <Processors/Merges/VersionedCollapsingTransform.h>
#include <Storages/MergeTree/MergeTreeInOrderSelectProcessor.h>
#include <Storages/MergeTree/MergeTreeReverseSelectProcessor.h>
#include <Storages/MergeTree/MergeTreeThreadSelectProcessor.h>
#include <Storages/MergeTree/MergeTreeDataSelectExecutor.h>
#include <Storages/MergeTree/MergeTreeReadPool.h>