Refactor and remove #prepare_relation method

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/65054

app/services/projects/base_move_relations_service.rb

@@ -10,12 +10,5 @@ module Projects
 
       true
     end
-
-    private
-
-    def prepare_relation(relation, id_param = :id)
-      # TODO: Refactor and remove this method (https://gitlab.com/gitlab-org/gitlab-ce/issues/65054)
-      relation
-    end
   end
 end

app/services/projects/move_deploy_keys_projects_service.rb

@@ -16,8 +16,7 @@ module Projects
     private
 
     def move_deploy_keys_projects
-      prepare_relation(non_existent_deploy_keys_projects)
-        .update_all(project_id: @project.id)
+      non_existent_deploy_keys_projects.update_all(project_id: @project.id)
     end
 
     # rubocop: disable CodeReuse/ActiveRecord

app/services/projects/move_lfs_objects_projects_service.rb

@@ -16,8 +16,7 @@ module Projects
     private
 
     def move_lfs_objects_projects
-      prepare_relation(non_existent_lfs_objects_projects)
-        .update_all(project_id: @project.lfs_storage_project.id)
+      non_existent_lfs_objects_projects.update_all(project_id: @project.lfs_storage_project.id)
     end
 
     def remove_remaining_lfs_objects_project

app/services/projects/move_notification_settings_service.rb

@@ -16,8 +16,7 @@ module Projects
     private
 
     def move_notification_settings
-      prepare_relation(non_existent_notifications)
-        .update_all(source_id: @project.id)
+      non_existent_notifications.update_all(source_id: @project.id)
     end
 
     # Remove remaining notification settings from source_project

app/services/projects/move_project_authorizations_service.rb

@@ -21,8 +21,7 @@ module Projects
     private
 
     def move_project_authorizations
-      prepare_relation(non_existent_authorization, :user_id)
-        .update_all(project_id: @project.id)
+      non_existent_authorization.update_all(project_id: @project.id)
     end
 
     def remove_remaining_authorizations

app/services/projects/move_project_group_links_service.rb

@@ -20,8 +20,7 @@ module Projects
     private
 
     def move_group_links
-      prepare_relation(non_existent_group_links)
-        .update_all(project_id: @project.id)
+      non_existent_group_links.update_all(project_id: @project.id)
     end
 
     # Remove remaining project group links from source_project

app/services/projects/move_project_members_service.rb

@@ -20,7 +20,7 @@ module Projects
     private
 
     def move_project_members
-      prepare_relation(non_existent_members).update_all(source_id: @project.id)
+      non_existent_members.update_all(source_id: @project.id)
     end
 
     def remove_remaining_members