Remove sc_network::NetworkService::register_notifications_protocol and partially refactor Grandpa tests (#7646)

* Remove sc_network::NetworkService::register_notifications_protocol

* Missing calls to .into()

* Wrong crate name

* [WIP] Fix Grandpa tests

* One more passing

* One more. Two to go.

* This one was actually already passing 🎉

* Last one compiles

* Progress

* grandpa: fix voter_persists_its_votes test

* Restore other tests

* Try spawn future later

Co-authored-by: André Silva <andrerfosilva@gmail.com>

substrate/client/finality-grandpa/src/communication/mod.rs

@@ -68,6 +68,8 @@ mod periodic;
 #[cfg(test)]
 pub(crate) mod tests;
 
+/// Name of the notifications protocol used by Grandpa. Must be registered towards the networking
+/// in order for Grandpa to properly function.
 pub const GRANDPA_PROTOCOL_NAME: &'static str = "/paritytech/grandpa/1";
 
 // cost scalars for reporting peers.

substrate/client/finality-grandpa/src/communication/tests.rs

@@ -62,8 +62,6 @@ impl sc_network_gossip::Network<Block> for TestNetwork {
 		let _ = self.sender.unbounded_send(Event::WriteNotification(who, message));
 	}
 
-	fn register_notifications_protocol(&self, _: Cow<'static, str>) {}
-
 	fn announce(&self, block: Hash, _associated_data: Vec<u8>) {
 		let _ = self.sender.unbounded_send(Event::Announce(block));
 	}