migrate pallet-nomination-pool-benchmarking to benchmarking syntax v2 (#6302)
Migrates pallet-nomination-pool-benchmarking to benchmarking syntax v2. Part of: * #6202 --------- Co-authored-by: GitHub Action <[email protected]> Co-authored-by: Guillaume Thiolliere <[email protected]> Co-authored-by: Giuseppe Re <[email protected]>