Correct duplicate attribute check (#10901)

Brackets got lost during the update, leading to an incorrect
precondition call.

patches/server/Fix-CraftMetaItem-getAttributeModifier-duplication-c.patch

@@ -13,7 +13,7 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
          this.checkAttributeList();
          for (Map.Entry<Attribute, AttributeModifier> entry : this.attributeModifiers.entries()) {
 -            Preconditions.checkArgument(!entry.getValue().getKey().equals(modifier.getKey()), "Cannot register AttributeModifier. Modifier is already applied! %s", modifier);
-+            Preconditions.checkArgument(!entry.getValue().getKey().equals(modifier.getKey()) && entry.getKey() == attribute, "Cannot register AttributeModifier. Modifier is already applied! %s", modifier); // Paper - attribute modifiers with same namespaced key but on different attributes are fine
++            Preconditions.checkArgument(!(entry.getValue().getKey().equals(modifier.getKey()) && entry.getKey() == attribute), "Cannot register AttributeModifier. Modifier is already applied! %s", modifier); // Paper - attribute modifiers with same namespaced key but on different attributes are fine
          }
          return this.attributeModifiers.put(attribute, modifier);
      }

patches/server/General-ItemMeta-fixes.patch

@@ -982,7 +982,7 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
 -        this.checkAttributeList();
 +        if (this.attributeModifiers != null) { // Paper
          for (Map.Entry<Attribute, AttributeModifier> entry : this.attributeModifiers.entries()) {
-             Preconditions.checkArgument(!entry.getValue().getKey().equals(modifier.getKey()) && entry.getKey() == attribute, "Cannot register AttributeModifier. Modifier is already applied! %s", modifier); // Paper - attribute modifiers with same namespaced key but on different attributes are fine
+             Preconditions.checkArgument(!(entry.getValue().getKey().equals(modifier.getKey()) && entry.getKey() == attribute), "Cannot register AttributeModifier. Modifier is already applied! %s", modifier); // Paper - attribute modifiers with same namespaced key but on different attributes are fine
          }
 +        } // Paper
 +        this.checkAttributeList(); // Paper - moved down