changes to nfts pallet for xcm integration (#14395)

* Use Incrementable from frame_support::traits

* Chore

* make incremental fallible and new nfts function for custom collection ids

* fmt

* fix benchmark tests nfts

* add test

* fmt

* add safety comment to CollectionId

* fmt

* add comments to Incrementable

* line wrapping

* rewrap comments

* address feedback

* fmt

* change unwrap for expect

---------

Co-authored-by: Jegor Sidorenko <jegor@parity.io>
Co-authored-by: parity-processbot <>

substrate/frame/nfts/src/features/create_delete_collection.rs

@@ -50,13 +50,8 @@ impl<T: Config<I>, I: 'static> Pallet<T, I> {
 			),
 		);
 
-		let next_id = collection.increment();
-
 		CollectionConfigOf::<T, I>::insert(&collection, config);
 		CollectionAccount::<T, I>::insert(&owner, &collection, ());
-		NextCollectionId::<T, I>::set(Some(next_id));
-
-		Self::deposit_event(Event::NextCollectionIdIncremented { next_id });
 		Self::deposit_event(event);
 		Ok(())
 	}