Fix stacks losing empty attr modifiers

Fixes #10686

patches/server/1044-General-ItemMeta-fixes.patch

@@ -260,7 +260,7 @@ index 8e0dd4b7a7a25a8beb27b507047bc48d8227627c..cf5d27ccc2225bac3aa57912f444f95d
  
      @Override
 diff --git a/src/main/java/org/bukkit/craftbukkit/inventory/CraftMetaItem.java b/src/main/java/org/bukkit/craftbukkit/inventory/CraftMetaItem.java
-index 0bc100430483f88bc7edf17645250b2862ccc1d5..03f9fff7c06bf5f166d6277e3aa6adb5f646042d 100644
+index 0bc100430483f88bc7edf17645250b2862ccc1d5..1f3927ec4a44bc001285869c96a67e687e7438da 100644
 --- a/src/main/java/org/bukkit/craftbukkit/inventory/CraftMetaItem.java
 +++ b/src/main/java/org/bukkit/craftbukkit/inventory/CraftMetaItem.java
 @@ -165,9 +165,10 @@ class CraftMetaItem implements ItemMeta, Damageable, Repairable, BlockDataMeta {
@@ -287,13 +287,15 @@ index 0bc100430483f88bc7edf17645250b2862ccc1d5..03f9fff7c06bf5f166d6277e3aa6adb5
          CraftMetaItem.getOrEmpty(tag, CraftMetaItem.NAME).ifPresent((component) -> {
              this.displayName = component;
          });
-@@ -880,9 +886,7 @@ class CraftMetaItem implements ItemMeta, Damageable, Repairable, BlockDataMeta {
+@@ -879,10 +885,8 @@ class CraftMetaItem implements ItemMeta, Damageable, Repairable, BlockDataMeta {
+     }
  
      void applyModifiers(Multimap<Attribute, AttributeModifier> modifiers, CraftMetaItem.Applicator tag) {
-         if (modifiers == null || modifiers.isEmpty()) {
+-        if (modifiers == null || modifiers.isEmpty()) {
 -            if (this.hasItemFlag(ItemFlag.HIDE_ATTRIBUTES)) {
 -                tag.put(CraftMetaItem.ATTRIBUTES, new ItemAttributeModifiers(Collections.emptyList(), false));
 -            }
++        if (modifiers == null/* || modifiers.isEmpty()*/) { // Paper - empty modifiers has a specific meaning, they should still be saved
 +            // Paper - don't save ItemFlag if the underlying data isn't present
              return;
          }