Remove the wither outline when using the bossbar on 1.9->1.8 (#604)

Adds metadata to the spawn packet to make the wither tiny so the player doesn't see a wither outline when the bossbar is on low health

Author: Usepot

common/src/main/java/com/viaversion/viarewind/protocol/v1_9to1_8/data/WitherBossBar.java

@@ -203,6 +203,7 @@ private void addWither() {
         entityData.add(new EntityData(2, EntityDataTypes1_8.STRING, title));
         entityData.add(new EntityData(3, EntityDataTypes1_8.BYTE, (byte) 1));
         entityData.add(new EntityData(6, EntityDataTypes1_8.FLOAT, health * 300f));
+        entityData.add(new EntityData(20, EntityDataTypes1_8.INT, 880));
 
         addMob.write(Types.ENTITY_DATA_LIST1_8, entityData);
         addMob.scheduleSend(Protocol1_9To1_8.class);