Move repository creation to the synchronized block

This ensures that we only call create on the repo once

ee/app/models/design_management/version.rb

@@ -98,10 +98,11 @@ module DesignManagement
     CREATION_TTL = 5.seconds
     RETRY_DELAY = ->(num) { 0.2.seconds * num**2 }
 
-    def self.lock_for_creation(project_id, &block)
+    def self.lock_for_creation(project_id, repository, &block)
       key = "lock_for_creation:#{name}:{#{project_id}}"
 
       in_lock(key, ttl: CREATION_TTL, retries: 5, sleep_sec: RETRY_DELAY) do |_retried|
+        repository.create_if_not_exists
         yield
       end
     end

ee/app/services/design_management/delete_designs_service.rb

@@ -37,7 +37,7 @@ module DesignManagement
     attr_reader :designs
 
     def delete_designs!
-      DesignManagement::Version.lock_for_creation(project.id) do
+      DesignManagement::Version.lock_for_creation(project.id, repository) do
         run_actions(build_actions)
       end
     end

ee/app/services/design_management/runs_design_actions.rb

@@ -7,11 +7,13 @@ module DesignManagement
     # this concern requires the following methods to be implemented:
     #   current_user, target_branch, repository, commit_message
     #
+    # Before calling `run_actions`, you should ensure the repository exists, by
+    # calling `repository.create_if_not_exists`.
+    #
     # @raise [NoActions] if actions are empty
     def run_actions(actions)
       raise NoActions if actions.empty?
 
-      repository.create_if_not_exists
       sha = repository.multi_action(current_user,
                                     branch_name: target_branch,
                                     message: commit_message,

ee/app/services/design_management/save_designs_service.rb

@@ -33,9 +33,7 @@ module DesignManagement
     attr_reader :files
 
     def upload_designs!
-      ::DesignManagement::Version.lock_for_creation(project.id) do
-        repository.create_if_not_exists
-
+      ::DesignManagement::Version.lock_for_creation(project.id, repository) do
         actions = build_actions
 
         [actions.map(&:design), actions.presence && run_actions(actions)]