**Describe the bug**
ClickHouse doesn't return affected rows via MySQL protocol for INSERT queries after 20.5+

**How to reproduce**
i create clear docker-compose environment for reproduce behavior MySQL + clickhouse + php + python
https://gist.github.com/Slach/aa67440ce856a3a53f64f92eeddfbc1b

**Queries to run that lead to unexpected result**
```
INSERT INTO default.t1(n) SELECT * FROM numbers(1000)
```

**Expected behavior**
MySQL protocol shall return affected rows field for INSERT queries (it works successful in 20.3 and 20.4)
![image](https://user-images.githubusercontent.com/105560/97867431-aa22ae00-1d2f-11eb-8caf-05431ffd29b3.png)

**Actual behavior**
![image](https://user-images.githubusercontent.com/105560/97867401-9f681900-1d2f-11eb-93cc-5ae6f1f5981b.png)
#include "MySQLHandler.h"
#include <limits>
#include <ext/scope_guard.h>
#include <Columns/ColumnVector.h>
#include <Common/NetException.h>
#include <Common/OpenSSLHelpers.h>
#include <Core/MySQL/Authentication.h>
#include <Core/MySQL/PacketsGeneric.h>
#include <Core/MySQL/PacketsConnection.h>
#include <Core/MySQL/PacketsProtocolText.h>
#include <Core/NamesAndTypes.h>
#include <DataStreams/copyData.h>
#include <Interpreters/executeQuery.h>
#include <IO/copyData.h>
#include <IO/LimitReadBuffer.h>
#include <IO/ReadBufferFromPocoSocket.h>
#include <IO/ReadBufferFromString.h>
#include <IO/WriteBufferFromPocoSocket.h>
#include <IO/WriteBufferFromString.h>
#include <IO/ReadHelpers.h>
#include <Storages/IStorage.h>
#include <boost/algorithm/string/replace.hpp>
#include <regex>
#include <Access/User.h>
#include <Access/AccessControlManager.h>
#if !defined(ARCADIA_BUILD)
#    include <Common/config_version.h>