Allow countState() syntax similar to count()

Why it matters

This feature simplifies syntax for aggregate functions by allowing users to write countState() without specifying explicit columns, improving usability and consistency with count(). It addresses issue #9338 to enhance the user experience when working with aggregate function states.

How to use it

Users can directly write queries using countState() wherever aggregate states are supported, just like using count(). No extra configuration or flags are needed.