Do not send empty upsert player info packets

There is no harm in this, but seemingly, some common mod blows up on this, and,
well, why eat buffer?

proxy/src/main/java/com/velocitypowered/proxy/tablist/VelocityTabList.java

@@ -166,7 +166,9 @@ public class VelocityTabList implements InternalTabList {
       return entry;
     });
 
-    this.connection.write(new UpsertPlayerInfoPacket(actions, List.of(playerInfoEntry)));
+    if (!actions.isEmpty()) {
+      this.connection.write(new UpsertPlayerInfoPacket(actions, List.of(playerInfoEntry)));
+    }
   }
 
   @Override