Automatically Select "Complex Key" Layout for Dictionaries with Complex Keys

Why it matters

This feature simplifies dictionary creation by automatically choosing the appropriate layout variant for dictionaries defined with complex keys, ensuring optimal performance and correct behavior without requiring manual configuration from the user.

How to use it

When creating a dictionary with a complex key, simply define the dictionary as usual. ClickHouse will detect the complex key and automatically apply the "complex key" layout variant without additional user intervention.