[#59866] fixed update contract

- https://community.openproject.org/work_packages/59866
- skip uniqueness check for short if short is deleted

app/contracts/custom_fields/hierarchy/update_item_contract.rb

@@ -52,6 +52,7 @@ class UpdateItemContract < Dry::Validation::Contract
 
       rule(:short) do
         next if schema_error?(:item)
+        next unless key?
 
         key.failure(:not_unique) if values[:item].siblings.exists?(short: value)
       end

spec/contracts/custom_fields/hierarchy/update_item_contract_spec.rb

@@ -38,6 +38,7 @@
     let!(:vader) { create(:hierarchy_item) }
     let!(:luke) { create(:hierarchy_item, label: "luke", short: "ls", parent: vader) }
     let!(:leia) { create(:hierarchy_item, label: "leia", short: "lo", parent: vader) }
+    let!(:starkiller) { create(:hierarchy_item, label: "starkiller", parent: vader) }
 
     context "when all required fields are valid" do
       it "is valid" do

spec/factories/hierarchy_item_factory.rb

@@ -31,6 +31,5 @@
 FactoryBot.define do
   factory :hierarchy_item, class: "CustomField::Hierarchy::Item" do
     sequence(:label) { |n| "Item #{n}" }
-    sequence(:short) { |n| "I #{n}" }
   end
 end