fix(clippy): Ignore clippy drop warnings in tests (#4081)

* Silence clippy drop warning in tests

* Allow unknown lints for new lints in nightly

zebra-network/src/peer/client/tests/vectors.rs

@@ -47,6 +47,9 @@ async fn client_service_ready_drop_ok() {
 
     let (mut client, mut harness) = ClientTestHarness::build().finish();
 
+    // If the readiness future gains a `Drop` impl, we want it to be called here.
+    #[allow(unknown_lints)]
+    #[allow(clippy::drop_non_drop)]
     std::mem::drop(client.ready());
 
     assert!(client.is_ready().await);

zebra-network/src/peer_set/set/tests/vectors.rs

@@ -56,7 +56,9 @@ fn peer_set_ready_single_connection() {
         // Get a ready future
         let peer_ready_future = peer_set.ready();
 
-        // Drop the future
+        // If the readiness future gains a `Drop` impl, we want it to be called here.
+        #[allow(unknown_lints)]
+        #[allow(clippy::drop_non_drop)]
         std::mem::drop(peer_ready_future);
 
         // Peer set will remain ready for requests