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 (function->arguments->children.size() < 2)
                {
                    ++i;
                    continue;
                }
                const auto * dict_name_ast = function->arguments->children[0]->as<ASTLiteral>();
                const auto * attr_name_ast = function->arguments->children[1]->as<ASTLiteral>();
                if (!dict_name_ast || !attr_name_ast)
                {
                    ++i;
                    continue;
                }
                const auto & dict_name = dict_name_ast->value.safeGet<String>();
                const auto & attr_name = attr_name_ast->value.safeGet<String>();
                String resolved_name = DatabaseCatalog::instance().resolveDictionaryName(dict_name);
                const auto & dict_ptr = context.getExternalDictionariesLoader().getDictionary(resolved_name);
                if (!dict_ptr->isInjective(attr_name))
                {
                    ++i;
                    continue;
                }
            }
            else if (!function_factory.get(function->name, context)->isInjective(Block{}))
            {
                ++i;
                continue;
            }
            
            auto args_ast = function->arguments;
            /** remove function call and take a step back to ensure