Create a migration to backfill the archived field in milestone

What does this MR do and why?

This migration will backfill the archived value for the milestones.

Screenshots or screen recordings

Screenshots are required for UI changes, and strongly recommended for all other merge requests.

Before	After

How to set up and validate locally

1. Make sure the Elasticsearch is enabled.
2. Open the rails console

bundle exec rails c

4. Run the following commands in the console.

require_relative 'ee/elastic/migrate/20230831152648_backfill_archived_on_milestones.rb' 
BackfillArchivedOnNotes.new(20230831152648).migrate

5. Check on the elastic that all the notes must have the archived. To check that run the following curl command on the terminal and make sure the count is 0

curl -XGET "http://localhost:9200/gitlab-development/_count" -H "kbn-xsrf: reporting" -H "Content-Type: application/json" -d'
{
  "query": {
    "bool": {
      "must_not": {
        "exists": {
          "field": "archived"
        }
      },
      "filter": {
        "term": {
          "type": "milestone"
        }
      }
    }
  }
}' | json_pp

Run time

~5 minutes

[1] pry(main)> batch_size = 9_000
=> 9000
[2] pry(main)> throttle_delay = 10.seconds
=> 10 seconds
[3] pry(main)> number_of_documents = 278_023
=> 278023
[4] pry(main)> (number_of_documents / batch_size) * throttle_delay
=> 300 seconds
=> ~ 5 minutes

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)

#423863 (closed)