Fix ancient client error caused by empty meta for < 1.11

Since modern versions don't immediately send metadata in spawn packets and 1.10 clients and lower have a slight oversight in the meta getting, every mob/player spawn spammed the client console with an error. Even though it is a harmless error, I figured people would like their client console not to get spammed anymore.

common/src/main/java/com/viaversion/viabackwards/protocol/protocol1_10to1_11/packets/EntityPackets1_11.java

@@ -134,9 +134,7 @@ public class EntityPackets1_11 extends LegacyEntityRewriter<Protocol1_10To1_11>
                 handler(getTrackerHandler(Type.UNSIGNED_BYTE, 0));
 
                 // Rewrite entity type / metadata
-                handler(new PacketHandler() {
+                handler(wrapper -> {
-                    @Override
-                    public void handle(PacketWrapper wrapper) throws Exception {
                     int entityId = wrapper.get(Type.VAR_INT, 0);
                     EntityType type = tracker(wrapper.user()).entityType(entityId);
 
@@ -150,6 +148,10 @@ public class EntityPackets1_11 extends LegacyEntityRewriter<Protocol1_10To1_11>
                             entityData.defaultMeta().createMeta(new WrappedMetadata(list));
                         }
                     }
+
+                    // Sub 1.11 clients will error if the list is empty
+                    if (list.isEmpty()) {
+                        list.add(new Metadata(0, MetaType1_9.Byte, (byte) 0));
                     }
                 });
             }
@@ -172,6 +174,13 @@ public class EntityPackets1_11 extends LegacyEntityRewriter<Protocol1_10To1_11>
                 map(Types1_9.METADATA_LIST); // 7 - Metadata list
 
                 handler(getTrackerAndMetaHandler(Types1_9.METADATA_LIST, Entity1_11Types.EntityType.PLAYER));
+                handler(wrapper -> {
+                    // Sub 1.11 clients will cry if the list is empty
+                    List<Metadata> metadata = wrapper.get(Types1_9.METADATA_LIST, 0);
+                    if (metadata.isEmpty()) {
+                        metadata.add(new Metadata(0, MetaType1_9.Byte, (byte) 0));
+                    }
+                });
             }
         });