Remove saddle slot group from enchantments in 1.21.5->1.21.4

Fixes #1033

Author: kennytv

common/src/main/java/com/viaversion/viabackwards/protocol/v1_21_5to1_21_4/rewriter/EntityPacketRewriter1_21_5.java

@@ -119,6 +119,12 @@ public RegistryEntry[] handle(final UserConnection connection, final String key,
                     updateTrim(entries, trimPatternRegistry ? "template_item" : "ingredient");
                     return super.handle(connection, key, entries);
                 }
+
+                if (key.equals("enchantment")) {
+                    updateEnchantment(entries);
+                    return super.handle(connection, key, entries);
+                }
+
                 if (!key.equals("wolf_variant")) {
                     return super.handle(connection, key, entries);
                 }
@@ -209,6 +215,20 @@ private void updateTrim(final RegistryEntry[] entries, final String itemKey) {
         });
     }
 
+    private void updateEnchantment(final RegistryEntry[] entries) {
+        for (final RegistryEntry entry : entries) {
+            if (entry.tag() == null) {
+                continue;
+            }
+
+            final CompoundTag enchantment = (CompoundTag) entry.tag();
+            final ListTag<StringTag> slots = enchantment.getListTag("slots", StringTag.class);
+            if (slots != null) {
+                slots.getValue().removeIf(tag -> tag.getValue().equals("saddle")); // Remove saddle slot
+            }
+        }
+    }
+
     private String visibility(final int id) {
         return switch (id) {
             case 0 -> "always";