test(acp): satisfy queue capacity lint

Signed-off-by: Brother Darryl <146fb160a3266e6165bfa385f6048c975eda9e21cf65da097a0b5ea7952532a5@buzz.block.builderlab.xyz>

crates/buzz-acp/src/queue.rs

@@ -4582,7 +4582,7 @@ mod tests {
             "all cap slots are reserved, so a new event must not create another preparation"
         );
         assert_eq!(q.withheld_native_steer[&ch].len(), MAX_PENDING_PER_CHANNEL);
-        assert!(q.queues.get(&ch).is_none());
+        assert!(!q.queues.contains_key(&ch));
     }
 
     #[test]