Fix sidekiq warning for ElasticNamespaceIndexerWorker

• Please check this box if this contribution uses AI-generated content (including content generated by GitLab Duo features) as outlined in the GitLab DCO & CLA

What does this MR do and why?

While working on another MR (cannot remember which one 🤷), I noticed some sidekiq warnings when running certain tests.

This MR addresses this sidekiq warnings.

🛠 with ❤ at Siemens

MR acceptance checklist

Please evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

MR Checklist (@gerardo-navarro)

• Changelog entry added, if necessary
• Documentation created/updated via this MR
• Documentation reviewed by technical writer or follow-up review issue created
• Tests added for this feature/bug
• Tested in all supported browsers
• Conforms to the code review guidelines
• Conforms to the merge request performance guidelines
• Conforms to the style guides
• Conforms to the javascript style guides
• Conforms to the database guides

Screenshots or screen recordings

No frontend changes. The console output of warnings is reduced when the test is executed.

How to set up and validate locally

1. Run the test => you will not see the sidekiq warning

bundle exec rspec ee/spec/models/elasticsearch_indexed_namespace_spec.rb ee/spec/services/elastic/index_projects_by_id_service_spec.rb ee/spec/workers/elastic_namespace_indexer_worker_spec.rb

1. Run the test again in the branch master => you will see the sidekiq warning