Avoid exception when redisson address is null

Author: laurit

instrumentation/redisson/redisson-common/javaagent/src/main/java/io/opentelemetry/javaagent/instrumentation/redisson/RedissonRequest.java

@@ -35,6 +35,7 @@ public static RedissonRequest create(InetSocketAddress address, Object command)
     return new AutoValue_RedissonRequest(address, command);
   }
 
+  @Nullable
   public abstract InetSocketAddress getAddress();
 
   public abstract Object getCommand();