**Describe what's wrong**

We have a nested field in a table.
The table is created using SET flatten_nested = 0.
When the server is restarted the field is no longer nested (only flattened arrays appear).

**Does it reproduce on recent release?**

version 22.2.3.1

**How to reproduce**

Create a table using:

` 
SET flatten_nested = 0            
` 
` 
CREATE TABLE test.test    
    (     
        id String,  
       nested_field Nested (nf1 String, nf2 String)  
    ) ENGINE = MergeTree ORDER BY id  
`

Recover the table structure using describe:
`
describe test.test
`
`
name           type
id             String
nested_field   Nested(nf1 String, nf2 String) 
`

Restart click-house server.

Recover the table structure using describe:
`
 name               type            
 id                 String                                                                                          
 nested_field.nf1   Array(String)                                                                                   
 nested_field.nf2   Array(String)                                                                                   
`

*Expected behavior**

Recover the initial structure of the table not he flatenned one.


}
        else
        {
            
            column_names_and_types.emplace_back(col_decl.name, std::make_shared<DataTypeUInt8>());
        }
        
        if (col_decl.default_expression)
        {
            /** For columns with explicitly-specified type create two expressions:
              * 1. default_expression aliased as column name with _tmp suffix
              * 2. conversion of expression (1) to explicitly-specified type alias as column name
              */
            if (col_decl.type)
            {
                const auto & final_column_name = col_decl.name;
                const auto tmp_column_name = final_column_name + "_tmp_alter" + toString(randomSeed());
                const auto * data_type_ptr = column_names_and_types.back().type.get();
                default_expr_list->children.emplace_back(
                    setAlias(addTypeConversionToAST(std::make_shared<ASTIdentifier>(tmp_column_name), data_type_ptr->getName()),
                        final_column_name));
                default_expr_list->children.emplace_back(
                    setAlias(
                        col_decl.default_specifier == "EPHEMERAL" ? 
                            std::make_shared<ASTLiteral>(data_type_ptr->getDefault()) :
                            col_decl.default_expression->clone(),
                        tmp_column_name));
            }
            else
                default_expr_list->children.emplace_back(setAlias(col_decl.default_expression->clone(), col_decl.name));