Is your feature request related to a problem or challenge?

Follow on #11093 and also there is another issue #11256 expect this

Describe the solution you'd like

There are some functions always returns non-null result, like count, array_agg, min/max and more.
We can optimize the query based on the nullability of the function, so it would be helpful if we could define nullability for each UDAF

Describe alternatives you've considered

No response

Additional context

No response