version 21.5.5.12 (official build)

I'm trying to change data type for a column that is used in the TTL expression.
It works well when the table is empty.
When the table is not empty, the mutation fails.
As a result the table ends up in an inconsistent state.

```
create table test
(
InsertionDateTime DateTime,
TTLDays Int32 DEFAULT CAST(365, 'Int32')
)
Engine=MergeTree()
order by tuple()
TTL InsertionDateTime + toIntervalDay(TTLDays);

Ok.

insert into test values (now(), 23);

Ok.

ALTER TABLE test modify column TTLDays Int16 DEFAULT CAST(365, 'Int16');

Code: 341, e.displayText() = DB::Exception: Exception happened during execution of mutation 'mutation_2.txt' with part 'all_1_1_0' reason: 'Code: 10, e.displayText() = DB::Exception: Not found column InsertionDateTime in block. There are only columns: TTLDays (version 21.5.5.12 (official build))'. This error maybe retryable or not. In case of unretryable error, mutation can be killed with KILL MUTATION query (version 21.5.5.12 (official build)) [DB Errorcode=341]

insert into test values (now(), 23);

Ok.

select table, column, type, sum(rows) rows, sum(column_bytes_on_disk) on_disk
from system.parts_columns where column like 'TTLDays'
group by database, table, column, type

table | column  | type  | rows | on_disk
------+---------+-------+------+--------
test  | TTLDays | Int32 |    1 |      86
test  | TTLDays | Int16 |    1 |      84
```
{
    FirstNonDeterministicFunctionMatcher::Data finder_data{context, std::nullopt};
    switch (command.type)
    {
        case MutationCommand::UPDATE:
        {
            auto update_assignments_ast = command.ast->as<const ASTAlterCommand &>().update_assignments->clone();
            FirstNonDeterministicFunctionFinder(finder_data).visit(update_assignments_ast);
            if (finder_data.nondeterministic_function_name)
                return finder_data.nondeterministic_function_name;
            
            [[fallthrough]];
        }
        case MutationCommand::DELETE:
        {
            auto predicate_ast = command.predicate->clone();
            FirstNonDeterministicFunctionFinder(finder_data).visit(predicate_ast);
            return finder_data.nondeterministic_function_name;
        }
        default:
            break;
    }
    return {};
}
ASTPtr prepareQueryAffectedAST(const std::vector<MutationCommand> & commands, const StoragePtr & storage, ContextPtr context)