ScalarUDF with zero arguments should be provided with one null array as parameter

[viirya]

Describe the bug

According to ScalarUDFImpl document, if the function has zero argument, it will be passed a single element slice which is a a null array to indicate the batch's row count. But currently it is provided a null scalar.

This is reported by @dadepo in #8866 (comment).

To Reproduce

#8866 (comment) provides a reproducible test.

Expected behavior

ScalarUDFImpl implementation, when it has zero argument, it will be passed a single element slice which is a a null array to indicate the batch's row count.

Additional context

No response