Updating a Nullable column value by using alter .... where ... causes to set another value!

ClickHouse version: 20.6.3.28
Engine: MergeTree
OS: Ubuntu 18.04.3 LTS

Steps to reproduce:
```sql
CREATE TABLE table1(
	id int,
	price Nullable(Int32)
)
ENGINE = MergeTree()
PARTITION BY id
ORDER BY (id);
INSERT INTO table1 (id, price) VALUES (1, 100);
ALTER TABLE table1  update price = 150 where id=1;
SELECT * FROM table1;
```
We expect the price to be `150`, but it's `93148480`:

```
┌─id─┬────price─┐
│  1 │ 93148480 │
└────┴──────────┘
```
Using `Decimal(9,2)` field instead of `Int32` would set the value  `932342.88` always. It seems there's a fixed value for each data type.

If we don't use such a `where` clause, it works correctly:
```sql
ALTER TABLE db1.table1  update price = 150 where 1=1;
┌─id─┬─price─┐
│  1 │   150 │
└────┴───────┘
```
{
        const ColumnWithTypeAndName & arg_cond = block.getByPosition(arguments[0]);
        bool cond_is_null = arg_cond.column->onlyNull();
        ColumnPtr not_const_condition = arg_cond.column;
        bool cond_is_const = false;
        bool cond_is_true = false;
        bool cond_is_false = false;
        if (const auto * const_arg = checkAndGetColumn<ColumnConst>(*arg_cond.column))
        {
            cond_is_const = true;
            not_const_condition = const_arg->getDataColumnPtr();