Hello, there. Run into the problem with DISTINCT expression. It works incorrectly on the main query if it was already applied to one of the subqueries bond with UNION ALL.

**How to reproduce**
Server version: 20.5.4.40. 19.17.6.36 was free of the bug.
Using Datagrip for running queries.
Non-default settings:
```
input_format_defaults_for_omitted_fields: 1
decimal_check_overflow: 0
joined_subquery_requires_alias: 0
```

Consider following query
```
select distinct number
from ((select number from numbers(10)) union all (select number from numbers(20)));
```
It works fine, returning 20 rows as expected.

But if we add distinct to subqueries (it doesn't matter to the first, the second or both)
```
select distinct number
from ((select distinct number from numbers(10)) union all (select distinct number from numbers(20)));
```

Then in 20.5.4.40 we'll see 30 rows with numbers from 0 to 9 duplicated.
However, `count(distinct number)` returns the correct number of rows.

if (settings.optimize_move_functions_out_of_any)
        optimizeAnyFunctions(query);
    
    if (settings.optimize_injective_functions_inside_uniq)
        optimizeInjectiveFunctionsInsideUniq(query, context);
    
    if (settings.optimize_aggregators_of_group_by_keys)
        optimizeAggregateFunctionsOfGroupByKeys(select_query);
    
    optimizeDuplicatesInOrderBy(select_query);
    
    if (settings.optimize_duplicate_order_by_and_distinct)
        optimizeDuplicateOrderByAndDistinct(query, context);
    
    if (settings.optimize_redundant_functions_in_order_by)
        optimizeRedundantFunctionsInOrderBy(select_query, context);
    
    if (settings.optimize_monotonous_functions_in_order_by)
        optimizeMonotonousFunctionsInOrderBy(select_query, context, tables_with_columns);
    
    if (settings.optimize_if_transform_strings_to_enum)
        transformIfStringsIntoEnum(query);
    
    optimizeLimitBy(select_query);
    
    optimizeUsing(select_query);
}
}