Use AccumulatorArgs::is_reversed in NthValueAgg #11668
Description
Is your feature request related to a problem or challenge?
The changes in #11564 introduced AccumulatorArgs::is_reversed. This indicates that the sort order of the aggregation is reversed.
The existing implementation of NthValueAgg tracks this as internal state. Instead of that use AccumulatorArgs::is_reversed.
Describe the solution you'd like
Refactor NthValueAgg to use AccumulatorArgs::is_reversed.
Describe alternatives you've considered
No response
Additional context
No response