Allow fallback names for protocols (#8682)

* Allow fallback names for protocols

* Apply suggestions from code review

Co-authored-by: Roman Proskuryakov <humbug@deeptown.org>

* Fix some issues

* Fix compilation after merging master

Co-authored-by: Roman Proskuryakov <humbug@deeptown.org>

substrate/client/network/test/src/lib.rs

@@ -742,6 +742,7 @@ pub trait TestNetFactory: Sized where <Self::BlockImport as BlockImport<Block>>:
 		network_config.extra_sets = config.notifications_protocols.into_iter().map(|p| {
 			NonDefaultSetConfig {
 				notifications_protocol: p,
+				fallback_names: Vec::new(),
 				max_notification_size: 1024 * 1024,
 				set_config: Default::default()
 			}