Add the archived in the MilestoneInstanceProxy

What does this MR do and why?

This MR is setting the boolean archived field value for the milestone documents if the migration add_archived_to_main_index is finished. Also setting elastic_index_dependant_association on milestone to synch the archived values for milestone documents

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Before	After

How to set up and validate locally

• Ensure Elasticsearch is enabled in the gdk

Case migration add_archived_to_main_index is not finished

• To simulate this case make an early return here

      def migration_has_finished?(name)
        return false if name.eql?(:add_archived_to_main_index)
        Rails.cache.fetch cache_key(:migration_has_finished, name.to_s.underscore), expires_in: CACHE_TIMEOUT do
          migration_has_finished_uncached?(name)
        end
      end

• Create a new milestone in any project that is allowed to use elasticsearch
• Check the Elastic that the new milestone should not have an archived field
• Now archive that project, and again check on Elastic, the archived field still should not be present for this milestone
• Again unarchive the project and make sure on Elastic, the archived field still should not be present for this milestone

Case migration add_archived_to_main_index is finished

• To be sure the migration is finished, run the following commands in the rails console. To start the rails console run the following command.

bundle exec rails c

• Now in the console run the following commands

require_relative 'ee/elastic/migrate/20230719144243_add_archived_to_main_index.rb'
AddArchivedToNotes.new(20230719144243).migrate

• Create a new milestone on any project
• Check the Elastic that the new note should have an archived field
• Now archive that project, and again check on Elastic, the archived field should be set to true
• Again unarchive the project and make sure on Elastic, the archived field should be set to false

This is a curl request you can use to check the milestone. Replace the project_id with the one you used for the testing

curl -XGET "http://localhost:9200/gitlab-development/_search" -H "kbn-xsrf: reporting" -H "Content-Type: application/json" -d'
{
  "query": {
    "bool": {
      "filter": [
        {
          "term": {
            "project_id": #{project_id}
          }
        },
        {
          "term": {
            "type": "milestone"
          }
        }
      ]
    }
  }
}' | json_pp

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #421464 (closed)

#423862 (closed)