Remove invalid designated users when moving experiment [SCI-6335] (#3722)

app/services/experiments/move_to_project_service.rb

@@ -31,6 +31,7 @@ module Experiments
             raise
           end
           sync_user_assignments(my_module)
+          clean_up_user_my_modules(my_module)
           move_tags!(my_module)
         end
 
@@ -119,6 +120,10 @@ module Experiments
       UserAssignments::GenerateUserAssignmentsJob.perform_later(object, @user)
     end
 
+    def clean_up_user_my_modules(my_module)
+      my_module.user_my_modules.where.not(user_id: @project.users.select(:id)).destroy_all
+    end
+
     def track_activity
       Activities::CreateActivityService
         .call(activity_type: :move_experiment,